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Full text of "Lectures on localization in diseases of the brain"

CHAECOT'S 



LOCALIZATION 



DISEASES OF THE BRAIN 



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LECTURES 

ON 

LOCALIZATION 

IN 

DISEASES OF THE BRAIN 

Delivered at the Faculte de MjSdecine, Paris, 1875 



J. M. CHARCOT 

Professor in the Faculty of Medicine of Paris ; Chief of the Salpitriire Hospital ; 

Member of the Academie de Midecine ; of the Clinical Society of London ; 

President of the Society Anatomigue ; former Vice-President 

of the Sociite de Biologie, etc.. etc. 

EDITED 

LIBRARY OF THE 



PittsbHii kikm of Mm% 

BOURNEVILLE .,_ ^ ^ '' _ 

iMOT TO BE REMOVED. 



translated by 
EDWARD P. FOWLER, M.D. 

NEW YORK 



Tio. 2 2.^^ 



NEW YORK 

WILLIAM WOOD & CO., 27 GREAT JONES ST. 

1878 



;>\^^ 



Copyright by 
WILLIAM WOOD & CO. 




Tfow's 

PursTiNG AND Bookbinding Co., 

205-213 East j'itfi St., 

NKW YORK. 



AUTHOR'S PREFACE. 



The exposition of the principles underlying the doctrine 
of cerebral localization seems to have now become a neces- 
sary chapter of introduction to the practical study of diseases 
of the brain. 

In the Lectures which Dr. Fowler has kindly taken the pains 
to submit to the appreciation of our American confreres^ I 
have selected, as occasion required, information furnished by 
normal anatomy, experimental physiology, and clinical ob- 
servation, illustrated by minute and methodical examination 
of organic lesions. 

I have always given precedence, however, to the last- 
mentioned order of testimony, convinced that, although 
normal anatomy and experimental physiology may serve to 
indicate the true direction ; still, clinical and pathological 
research is necessary (in case of the human subject) to a final 
judgment and to the furnishing of proof . 

I shall consider it as a great honor if my book should be 
favorably received in a country where instructors in neural 
pathology are represented by scientists such as my friend 
W. Mitchell, and various others whom I might enumerate. 



iv author's preface. 

In any event, I cannot sufficiently thank Dr. Fowler for 
the care which he has bestowed upon the translation, and I 
unhesitatingly say that it appears to me a model, both of 
scrupulous exactitude in rendition of the original meaning, 
and as a clear and unexceptionable style of English. 

J. M. Charcot. 

Paris, Oct. 26, 1878. 



TRANSLATOR'S PREFACE. 



No excuse is required for contributions to medical litera- 
ture which are calculated to increase exactitude of expres- 
sion, ideas, and knowledge, thereby assisting to elevate 
medical Art to the higher plane of Science. 

These lectures are a bold example of that cast, as in- 
deed are all of Charcot's teachings and writings. 

It is too late to introduce our distinguished author to 
the medical profession, for wherever medicine is taught 
as a science his works are already known and prized, and 
have been translated into nearly every modern language. 
This, however, is the first volume which has been pub 
lished in this country. 

Charcot's superstructures are always built with great 
care and reserve upon the secure basis of induction, though 
he is none the less resplendent in the rich harvest of de- 
duction which naturally follows. 

The translator cannot refrain from expressing his con- 
viction that the perfecting of medical knowledge depends 
mainly upon those investigators of which Charcot is so 
brilliant and so sound a representative. 

New York, July, 1878. 



CONTENTS 



FIRST LECTURE. 

PAGE 

Localization in Cerebral Diseases i 



SECOND LECTURE. 
Structure of the Gray Substance of the Brain 14 



THIRD LECTURE. 

Considerations upon the Normal Structure of the Gray Substance 

of the Convolutions 24 



FOURTH LECTURE. 
Parallel between Spinal and Cerebral Lesions 33 

FIFTH AND SIXTH LECTURES. 
Arterial Circulation in the Brain 41 

SEVENTH LECTURE. 

Circulation in the Central Masses (Gray Ganglia and the Internal 

Capsule) 59 

EIGHTH AND NINTH LECTURES. 
Central Arteries. — Isolated Lesions of the Gray Ganglia 70 



Vni CONTENTS. 



TENTH LECTURE. 

PAGE 

Cerebral Hemianaesthesia (Continued). — Crossed Amblyopia. — Lat- 
eral Hemicipia 90 



ELEVENTH LECTURE. 
Origin of the Cerebral Portion of the Optic Nerves loi 

TWELFTH LECTURE. 
Secondary Degeneration 115 



LECTURES UPON LOCALIZATION 



DISEASES OF THE BRAIN. 



FIRST LECTURE. 

LOCALIZATION IN CEREBRAL DISEASES. 

Summary : —Preamble. — Apparent Aridity of the Study of Cerebral 
liOcalization. — Principles of Ijocalizatioii.— The Kncephalon in a 
3Ioi'pliological Point of Vie-\v. — Xecessity of an Exact Nomenclature. 
— Topography of the Convolutions. — Importance of Comparative 
Anatomy.— Convolutions of the Brain of the Monkey ; Frontal, Pari- 
etal, and Sphenoidal Lio'jes. — Psycho-motor Centres. — Differences in 
the Composition of the Gray Substance in the A'arious Regions of 
the JBrain. 

Gentlemen : 

I. We will devote the first part of this year's course to 
the anatomico-pathological study of the encephalon. Every- 
one in an audience of medical practitioners will recognize the 
importance of this subject. But, with some, the lack of an 
attractive exterior has given it an unfortunate reputation ; 
in this particular I hope to inspire you with a different sen- 
timent. Through a method already often employed, aided 
also by a certain amount of patience and perseverance — and 
that will not be lacking on my part, I assure you — I think 
we shall accomplish this task without undue fatigue or diffi- 
culty. 

To avoid leading you unprepared into the domain where 



2 DISEASES OF THE BRAIN. 

we shall journey together, I will make, by way of an intro- 
duction, some observations concerning general facts, the ap- 
plication of which facts will be obvious at each subsequent 
step. 

I have little faith in the value of generalities when unac- 
companied by their material substructure, and especially as 
concerns pathological anatomy. I will therefore supply such 
groundwork by furnishing a certain number of actual illustra- 
tions. These examples will be taken from the most impor- 
tant chapter in encephalic pathology, that treating of locali- 
zation in cerebral diseases. 

Various reasons have decided my choice of subject. In 
the first place, it is one of those fields of inquiry where the 
advantage of associating clinical with anatomico-pathological 
studies is most conspicuously evident ; upon the principles of 
cerebral localization is founded that which may be called 
regional diagnosis of encephalic diseases, that ideal toward 
the realization of which, in this special section of pathology, 
should be directed all the efforts of clinical teaching. 

Then, again, the question of cerebral localization has en- 
tered a new phase, and is now enlisting world-wide attention. 

We should not make undue sacrifices to fashion, but on 
the other hand we must not undervalue the attractions and 
the new facts presented by recent investigations. 

In a thesis offered at the last conconrs d aggregation de 
medecine, this interesting chapter has been handled with 
great ability by my friend and old pupil. Dr. Lepine, agrege 
of that faculty. I shall be happy to utilize the delicately dis- 
criminated observations which abound in that work, and to 
turn to profit the wealth of erudition which the author has 
there accumulated. 

It is understood, of course, that in these preliminary lectures 
we can give only a free outline. The subjects which I shall 
introduce should be resumed later, submitted to a more pro- 
found study, and examined in their most minute details. 

II. — Long explanations are unnecessary to convey what is 
5ieant by localization in cerebral physiology and pathology. 



LOCALIZATION IN CEREBRAL DISEASES. 3 

The term has long since become a common one, and its 
meaning is well known, I will therefore only remind you 
that the principles of cerebral localization rest upon the fol- 
lowing proposition : The encephalon does not represent an 
homogeneous organ, a unit, but rather an association, or a 
confederation, composed of a certain number of diverse 
organs. To each of these organs belong distinct physio- 
logical properties, functions, and faculties. Now, the physio- 
logical properties of each one of these parts being known, it 
becomes possible to deduce therefrom the conditions of a 
pathological state ; this being of course but a greater or less 
modification of the normal state, and not a result of the inter- 
vention of new laws. 

We will employ the varied knowledge furnished by normal 
anatomy and experimental physiology, together with those 
clinical observations which have been rendered reliable by a 
methodical and minute examination of organic lesions, and 
thus endeavor to ascertain upon what foundation this propo- 
sition rests. The importance and the decisive results which 
depend upon these last-named examinations cannot be over- 
stated. For although normal anatomy and experimental 
physiology may often suggest the true direction towards 
localization, still nothing but the actual examination of organic 
lesions will permit a final decision and furnish the proof, at 
least so far as concerns the special subject of our studies — man. 

A. This brings us to an examination of the encephalon 
under its morphological aspect. It is understood we do not 
attempt a rigorous description ; I propose only to draw a 
general outline, a knowledge of which is indispensable to our 
object. To simplify a very complex situation, I will confine 
myself to the brain ; that is, to that mass of nervous substance 
composed of two hemispheres and situated at the superior 
extremity of what are called the cerebral peduncles (crura 
cerebri). 

The two hemispheres are nearly symmetrical, and so nearly 
identical in their structure that whatever may be said of the 
one may, anatomically speaking, rigidly apply to the other. 
Each one is enveloped in a layer of gray substance. The 



4 DISEASES OF THE BRAIN. 

central part is formed by a mass of wliitc substance, in which 
are furrowed the ventricles, and where are also seen, as if 
locked together, the central ganglionic masses, namely, the 
tJialanii optici and the corpora striata. 

A transverse section made to intersect the corpora mammil- 
laria best demonstrates the main features of the reciprocal 
relations of the central parts. (Fig. i.) 




uxtr 

Lenticular Audi 

Hera of Aamaon 



Sphenoidal Hont 
onat.Venlricle 



'ill Post . cerebral Arteries 



Fig. I. — Vertico-transverse section of the brain, posterior to the tubercula mam- 
millaria ; anterior to the peduncles. 

Immediately above the protuberance you see the inferior 
face of the crura cerebri, the inferior portions of which issue 
mainly from the anterior bulbs of the pyramids. 

From the lower up to the middle part of the section, you 



LOCALIZATION IN CEREBRAL DISEASES. 5 

will see two large, white tracts which rim divcrgingly towards 
the cortical portions of the hemispheres. They are between 
two masses of gray substance, the one internal and superior, 
the other external and inferior. These two tracts are the pro- 
longations of the crura cerebri to the cerebral hemispheres. 

The ci-ura cerebri, which are at first irregularly quadrilateral, 
become horizontally flattened as they enter the hemispheres, 
running from behind forwards, and when they have passed 
the narrow strait of the ganglionic region they open and 
spread in every direction — in front towards the frontal ex- 
tremity, in the centre towards the parietal regions, behind 
towards the occipital extremity. Burdach calls the flattened 
interganglionic parts of the peduncles the internal capsules ; 
the subsequent expansion has been called by Reil the cou- 
ronne rayonnante, diverging fibres ; the foot of the diverg- 
ing fibres is where the peduncles emerge above the cerebral 
ganglia. The peduncles as they enter the hemispheres some- 
what resemble a spread fan. 

Let us now describe briefly — returning to it later — the re- 
spective locations of the cerebral ganglia in regard to this fan. 

When, upon making the classic section, the lateral ventri- 
cles were opened, you will remember that there protruded 
upon the surface two masses of gray substance ; the anterior 
and external one is shaped like a comma ox d. glass tear, the 
large extremity or head of which is anterior and the small 
end or tail (cue) is posterior and lateral, and is called the 
nucleus caudatus of the corpus striatum ; the other mass is 
internal and posterior, and is ovoid — this is the thalamus opti- 
cus ; the thalami optici are separated by the base of the third 
ventricle. 

These two intraventricular gray masses, the nucleus cau- 
datus of the corpora striata and the thalami optici, rest 
above and within the peduncular fan. Below the fan, and 
more voluminous than the other two, is found a third nucleus 
having much the form of a plano-convex lentil, from whence 
the name, lenticulares glandulcB (Burdach).^ As it is of 

' In French nomenclature it is called the extra ventricular nucleus of tlie 
corpus striatum. 



6 DISEASES OF THE BRAIN, 

equal extent antero-postcriorly with tlic other two, it will 
always be found upon transverse sections (frontal sections of 
the Germans), perpendicular to the great interhemispheric 
fissure, whenever the others are met with. 

The study of transverse sections, made at methodical inter- 
vals from before backward, and commenced from certain 
starting-points upon the base of the hemispheres, is indispen- 
sable to a familiarity with the mutual relations of the ganglia, 
as well as their relations to the peduncles, and it is also 
essential to the clinicien, whose duty is to precisely deter- 
mine the parts diseased. 

I will describe, as our studies may require, the appearance 
of these transverse sections. An understanding of one of 
the most posterior of these sections, made immediately in 
front of the crura cerebri (Fig. i), is all that we need at the 
present moment. 

You here see the flattened portions of the crura, the inter- 
nal capsules. Within these are seen the surfaces of the thai- 
ami optici and the queues of the corpora striata. To the 
outer side of the internal capsule is seen, with its three seg- 
ments, the lenticular nucleus of the corpus striatum. These 
gray nuclei are possibly so many centres endowed with dis- 
tinct properties and functions ; but it must be remembered 
that this is not yet positively demonstrated. Still external 
to the lenticular bodies you will discover, in succession, the 
external capsules, the outer walls (little white unnamed 
bands), and lastly the gray layers of the island of Reil. 

I have no intention to engage at present with details of 
structure ; I wish only to insist upon these designations 
given, however minute they may seem ; for years past I 
have persisted in introducing them into the French nomencla- 
ture only because I have considered them of the highest 
utility when, as upon autopsy, it is desirable to indicate the 
exact locality of the lesion. Who would dare to affirm that 
such or such a region, which has no place in our nomencla- 
ture, is not possessed of an importance even of the first 
order ? Besides, how can such region be described in a 
record of autopsy if it has no recognized name ? The names 



LOCALIZATION IN CEREBRAL DISEASES. 7 

which I supply furnish many starting-points, and their utiHty 
is therefore incontestable. Is a good strategic chart ever too 
complete ? It is in thus precisely specifying the spot occu- 
pied by a hemorrhagic centre — the external or internal cap- 
sules, the gray ganglia, the foot of the diverging fibres, etc. — 
that you will be able to prove whether there are symptomatic 
differences of location such as might aid prognosis. An 
example, presented in a case of cerebral haemorrhage, will 
serve as proof that this is no superfluous labor. If a ha;m- 
orrhagic centre involves only the external capsule, what- 
ever be the extent of the lesion, the patient in all probability 
will recover without persistence of hemiplegia or any other 
infirmity ; but, on the contrary, if it be the internal capsule 
that is involved, and the patient survives, there will remain 
persistent paralysis and permanent contractions. 

The importance of an exact and minute study of the shape 
and plan of the brain, joined to an appropriate nomenclature, 
is especially shown when dealing with the comwliitions upon 
the surface of hemispheres. For a long time these convolu- 
tions were supposed to be, as it were, the result of chance, 
and thus they escaped any close description. Leuret and 
Gratiolet demonstrated that, on the contrary, there was an 
orderly plan, which could be traced from the inferior mam- 
malia, by the way of the monkey, up to man. 

Moreover, there are among the convolutions those which 
can be c?\\^<\ fundaviciital, for the reason that their locations 
and relations are absolutely fixed ; then again there are those 
which may be termed secondary, or accessory, and which 
must be studied abstractly, because they are variable. 

You will easily comprehend that without a good topog- 
raphy of the convolutions it is quite impossible to take one 
step in the more important knowledge of cerebral localiza- 
tions. For example, how can we speak of lesions produc- 
ing aphasia unless we are able to determine precisely the 
location and form of the third frontal convolution ? How 
could we locate in man the regions called psycho-motor, 
which the studies of Fritsch, Hitzig, and Ferrier have discov- 
ered in animals, if no notice be taken of the convolutions and 



8 DISEASES OF THE BRAIN. 

furrows upon the gray substance of the parietal lobes and the 
posterior portions of the frontal lobes ? How many observa- 
tions which might have thrown light upon these interesting 
questions of localization arc valueless, for the reason that, 
from an insufficient knowledge of the altered parts, an exact 
description has not been possible ! In order to obviate as 
far as possible that lack in the anatomical description of the 
normal brain, I have for a long time past habituated myself 
to outlining the locations of brain-lesions upon schemes de- 
signed from nature. In the absence of these precautions 
no ideas can be obtained which are not open to criticism. 
Still, this study has not so many difficulties as may at first be 
supposed. If the most complete knowledge has not yet found 
its way into classic works, it nevertheless abounds elsewhere. 
Beyond the standard works of Leuret and Gratiolet, Bishoff, 
Arnold, Turner, etc. (a familiarity with which is indispen- 
sable\ I recommend to your use the little manual of Ecker/ 
A\hich contains good topographical plates, accompanied with 
a simple nomenclature, together with synonyms. Through 
my advice Duret has employed these plates in his important 
menioire upon the circulation in the encephalon. An excel- 
lent work upon this subject, also, is a thesis by Gromier, written 
under the inspiration of Paul Broca, and entitled, " Study 
upon Cerebral Convobitio7is in Man and Monkey. 1874." 

Comparative anatomy is also a powerful adjunct in the 
study of the convolutions. Between the monkey and man, 
for example, the resemblance is striking, ~ as concerns the fun- 
damental convolutions and furrows, and that arrangement, 
which in man is somewhat unintelligible, is explained in the 
brain of the monkey by reason of its greater simplicity. I 
therefore will exhibit a sketch of the convolutions as ob- 
served in the monkey before considering those of the human 

' Die HirWiUiiidimgen des Meiischen nach eigenen Untersuchungen insbesondere 
iiber die Entwickhing derselben beiin Fotus uttd mit Rucksicht aiif das Bedarf- 
iiiss der Arzte. Brunswick, 1869. There is an English translation of the work. 

'■' Upon this subject, read in the last edition of Darwin's " The Descent of 
Man" (London, 1874)', Professor Huxley's interesting note (p. 199), on the resem- 
blances and differences in the structure and development of the brain in man and 
apes. 



LOCALIZATION IN CEREBRAL DISEASES. 



brain. This study possesses additional interest from the fact 
that actual experiment has already located upon some of the 
convolutions of the monkey brain those points known ^.s psycho- 
motor, thus furnishing a base for clinical and anatomico-patho- 
logical research concerning their existence in corresponding 
points of the human brain. 

Here is a lateral representation of a monkey's brain (Fig. 2) 



Motor- centers for rptaiica i 
of headdneck^' 



l^t. front. cony. .Ascending parietal conv, 
2f front. conv. 1 \ ,-. . -c , , 

Sffronr.conv:, I \ \ fissure of Rolando 

\ \ IMolor centers of fore-legs 
_r- .-.■ /^..-T I'lJc'' ''^''■^':i ->-icbule-of the ascend _p3r. Conv. 
Curvedfrcnit.fiss^^^V^s=::^S^,|,. -.^ sX , |Y^!t~^'.:\lotor centers ofhiTid-lerfg. 

V'Q-t:->^ ~"\' / '■!'! :-„Jt-i--ii./Tor certain movemenls. 
»/■ . . .r / ->-^'>~3:'''''~~^\/' ^^'Ivv^^"^ iGihl/TTv of eyes' aiid vision. 

morenients of ^ 
face. 



Orbital lob> 




1- ">-^^<:^7///f 



lissTe of 5)lvius 




Motor-centers.of tongue, , 
jaws.etc- 

Asc.fronlcon-V. 

Motai^ centers for 'hearing" & ,' 

movements 'cf th^ ear 



Fig. 2. — E.x'ternal face of the brain of :he magot monkey (Pithccus Innuus). 
— Broca and Gromier. 

taken from the work of Gromier. It is a brain of the magot 
{Pithec7is innuus), a monkey of somewhat low type. I will 
give a description of the external face of the hemisphere only, 
the internal and inferior faces being of less importance to our 
subject. 

First, two long fissures are seen, the fissure of Rolando 
and that of Sylvius. These fissures converge and constitute 
the posterior border of the external face of the frontal lobe. 

Further back is seen another fissure, the parieto-occipital. 
In the monkey this fissure very clearly separates the occipital 
lobe from the temporal and parietal lobes. This separation 
is much less marked in the human brain on account of the 
overlying convolutions [plis de passage) which more or less 
conceal it. 



lO DISEASES OF THE BRAIN. 

The parietal and sphenoidal lobes are less distinguishable 
in the monkey, and to complete the outline it is necessary to 
prolong the fissure of Sylvius with an imaginary line passing a 
convolution called the ^yrns angiilaris (pli courbc.) 

The external surface of the cerebral hemisphere is divided 
into four lobes, the frontal, parietal, sphenoidal, and occipital. 

Each of these lobes is subdivided by fissures or sulci of 
the second order into secondary lobes, called convolutions. 

Frontal Lobes. — TJie prcecentral or curved frontal fissure 
in the frontal lobe is the anterior border of a convolution 
lying parallel with the fissures of Sylvius called the ascending 
frontal convolution, and to give it more interest, I will ob- 
serve that in its superior extremity Ferrier locates the motor 
centres of the opposite upper limbs. 

Fissures running at right angles with the curved frontal 
fissure divide the remainder of the frontal lobe into three 
convolutions. ist. In the posterior extremity of the first or 
upper convolution Ferrier places the motor centre for the 
movement of the head ; 2d. Upon the same authority the 
posterior part of the second or middle convolution is the 
centre of facial movements ; 3d. In the third or lower convo- 
lution is located, in the monkey, a motor centre for move- 
ments of the lips and tongue ; to this part is ascribed in 
man the faculty of articulate speech — the third convolution, 
or as the English call it, Brocds convolution. I do not wish 
to be less French than are the English, and in adopting the 
term I am happy to recognize the signal service which our 
colleague has rendered to the cause of cerebral localization. 

Parietal Lobe. — The parietal lobe, so difficult of study in 
man, is on the contrary very easy in the monkey. The 
interparietal fissure divides it into two secondary lobes : ist. 
The superior parietal lobe, where Ferrier locates the centre 
for movements of the lower limbs ; 2d. The inferior parietal 
lobe ; 3d. A fissure, more marked in the higher monkeys, sepa- 
rates the parietal lobes from the ascending parietal convolu- 
tion. In a part of the ascending parietal convolution, and 
extending to the superior extremity of the ascending frontal 
convolution, is the motor centre of the upper limbs. 



LOCALIZATION IN CEREBRAL DISEASES. 



II 



Sphenoidal Lobe. — The situation of the sphenoidal lobe is 
easily understood. Upon the convex face of the hemisphere 
it is bounded by the lower border of the hemisphere and by 
the fissure of Sylvius. The parallel fissure, called thus 
because it is parallel to the fissure of Sylvius, divides the lobe 
into two parts. In the upper part is found the marginal con- 
volution, and at the posterior end of the fissure, the gyrus 
angularis, the removal of which Ferrier says produces tem- 
porary blindness of the opposite eye. 

Occipital Lobe. — A transverse furrow separates this lobe 
into two parts. For the present there is nothing special to 
be said of it. 

After this brief survey of the cerebral convolutions in the 
monkey, the corresponding ones in man become more sim- 



Sup. jaiifit'I J^otule, 
/ 

of/Rolando,, 



lier -parietal ^ 
\fissiire»- ^ 




Hssure cf Sylvia- 



'araUfii'fissure. 



Fig. 3. — Convex surface of a hemisphere of the human brain (parietal lobe partly 
schematic.) 

plified, as proved by the recapitulation which I will now 
give, using for that purpose a plate from Foville's beautiful 
work (Fig. 3). 

You observe that the fissure of Sylvius and the fissure of 
Rolando furnish the inferior and posterior borders of the 



12 DISEASES OF THE BRAIN. 

frontal lobe, in which lobe you may notice the ascending 
frontal (or anterior parietal) convolution and the first, second 
and third frontal convolutions. (Fig. 3.) 

The parieto-occipital fissure, on account of its overlying 
folds (//« de passage), affords but a confused separation 
between the occipital, parietal, and sphenoidal lobes. 

Back of the fissure of Rolando, between that and the inter- 
parietal fissure, is the ascending parietal convolution ; above 
and back of the interparietal fissure you will find, successively, 
the superior and inferior parietal lobules and the gyrus angu- 
laris. 

In the sphenoidal or temporal lobe, the brain, both of the 
human and the monkey, has a fissure that extends to the 
gyrus angularis ; this is the parallel fissure ; between it and 
the fissure of Sylvius lies the first temporal convolution ; 
below and posterior are the two other temporal convolutions. 

The parietal lobe, the fissure of Sylvius and that of Rolando, 
afford a sufficient number of starting-points to serve as guides 
in autopsy. 

III. — Thus the surface of the brain is marked off into divi- 
sions, the invariableness of which cannot be misunderstood. 
Do these various fundamental convolutions represent distinct 
functional centres ? A consideration of only the external 
achitecture cannot resolve the question. 

We will now resort to the microscope to ascertain whether 
a comparative study of structure in the various regions of the 
cortex will not furnish still more significant information upon 
this subject. 

Unaided vision has long since recognized differences of 
structure in the gray substance, according to the encephalic 
region examined. From this point of view let us examine, 
for example, the lower portion of the occipital lobe. In those 
parts of the lobe which surround the posterior cornua of the 
lateral ventricles, the gray substance is not of that almost 
uniform appearance which belongs to other regions of the 
brain, as, for instance, to the anterior lobes. Vicq d'Azyr 
observed that in those parts of the occipital lobes the gray 



LOCALIZATION IN CEREBRAL DISEASES. 1 3 

substance of the conv^olutions was very clearly divided into 
two secondary bands, separated by a white line which is still 
called the band of Vicq d' Azyr. In this respect also the un- 
assisted eye can distinguish between the gray substance of 
the cornua Ammonis, the isle of Reil, and that of other 
regions of the hemispheres. 

To appreciate the value of these facts it is necessary to 
enter more into detail. 



SECOND LECTURE. 

STRUCTURE OF THE GRAY SUBSTANCE OF THE BRAIN. 

Summary: — General Structural Character of the Brain-Cortex. — 1st; 
Ganglionic or Nerve Cells ; Pyraimidal Cells. — Views Respecting the 
Nerve-Cflls of the Anterior Corniia of the Gray Substance of the 
Spinal Corel (Motor-Cells) ; Size, Form, Body, iVuclcus, IVueleolus, Pro- 
toplasina, Fibrillre and Granules; Xerve Network; Prolongations 
of Protoplasnia ; Nerve-Prolongations. — Comparison of the Motor 
Nerve-Cells of the Spinal Cord ^vith the Pyramidal Cells. — Pyrani- 
idal Cells ; Size ; the Small Cells; the Large or Giant Cells ; Composi- 
tion of the Cells ; Shape, Body, Nucleus, Nucleolus ; Cellular Prolonga- 
tions; Pyramidal Prolongations; Prolongations which Recall those 
of the Protoplasma ; Basal Prolongations. — 'jd and 3fl ; Elements of 
Globular Cells; Elongated Cells. — Ith and 5th; Medullary Tubes; 
Neuroglia or Amorphous Cerebral Substance. — Relations between 
the Elements ; Five-layer Type. — The Importance of Exauiining the 
Gray Substance of each Convolution. — Two Divisions, Structurally, 
of the Gray Substance. — Labors of Betz. 

Gentlemen : 

I. The structure of the gray substance, in whatever region 
of the hemispheres, presents certain general characteristics 
which should be examined before approaching distinctive 
characteristics. All parts of the cortex are composed of 
essentially the same elements. Each one of the composing 
elements may present important relative deviations from the 
standard type, according to the region observed ; and in a 
regional stjidy of the gray substance great weight should be 
given to the different proportion and manner in which these 
elements are distributed in different parts. 

After having examined these components individually, we 
will investigate as to how they combine to form the gray 
substance. Our description will commence with those ele- 
ments which play the principal role, that is, those ganglionic 



THE GRAY SUBSTANCE OF THE BRAIN. 1 5 

or ncrvc-cclls which are the special characteristic elements 
of this region ; they are usually called the pyraviidal cells. 

In order to fully appreciate the morphological properties 
of these elements, perhaps it is best not to confine our atten- 
tion to them exclusively. I have thought best to employ the 
comparative method, reposing upon the common saying : 
"Light is born from contrast" i^' La linnitre nait dii con- 
trast e "). 

I will first recite the principal traits of that nerve cellular 
element which is at present best understood : I refer to the 
nervc-cclls of the anterior cor una of the gray substance of the 
spinal cord, called the motor cells. The abridged description 
which I will give of these nerve-cells will serve as a type. 
In the comparisons that follow I shall point out more than 
one difference, but I shall also make special mention of more 
than one remarkable analogy. 

The motor cells are cells without a distinct membrane, the 
diameters of which are variable, though not deviating greatly 
from 0.050 m. Gerlach, however, says that they may reach 
to 0.120 m. ThQxr form is more or less globular, rarely 
elongated. The bodies are composed of protoplasm which 
appears granular when seen in the non-living state, but in the 
serum, or after the action of osmic acid upon the fresh cell, 
it appears to be composed of a transparent protoplasm in the 
interior of which, as Shultz has demonstrated, exist numer- 
ous fibrillcB. These fibrillae by post-mortem alterations 
change to granules. The cell contains a nucleus and a 
brilliant nucleolus. I also generally observe in the proto- 
plasm, even in its physiological condition, the presence of 
brown / igm cntary gra n n les . 

One of the most important peculiarities of these cells, how- 
ever, is that they are armed with numerous prolongations, 
which have a voluminous trunk as they leave the cells, and 
which become smaller in proportion as they extend and 
divide (dichotomously). The last of these ramifications are 
extremely minute, and it is difficult to trace them for any 
distance. 

Gerlach, after the use of preparations of chloride of gold, 



l6 DISEASES OF THE BRAIN. 

asserts that these ramifications terminate in a sort of anas- 
tomosing network which he called rescau ncrvcux. These 
prolongations are composed, like the cell-bodies themselves, 
of granular protoplasm and long parallel filaments, which 
may be traced into the body of the cells. They are called 
protoplasmic prolongations, in order to distinguish them from 
another species of prolongation which I will now describe. 

A German histologist, Deiters, some years ago discovered 
an important fact which has since been verified by all anato- 
mists. It is that the greater part, if not all, of the motor 
cells possess, besides the prolongation which we have de- 
scribed, a prolongation (one only for each cell) which charac- 
teristically differs from the others. These prolongations bear 
the name of ncrvc-prolongations^ and the reason of that quali- 
fication will be presently understood. It proceeds from the 
body of the cell, or from one of its larger prolongations, in 
the form of a very slender filament, but which, little by little, 
becomes more voluminous. This prolongation does not 
ramify, and it becomes less brightly colored by action of 
carmine than do \\\c protoplasviic prolongations. 

If followed a sufficient distance, it is found to be enveloped, 
the same as an ordinary nerve, with a myeline c)'lindcr, so 
that it may be considered as a cylinder axis at its origin, and 
at a certain distance as a complete nerve. The connection 
of the nerve-cells with the tubes of the medullary substance, 
by means of these prolongations (nerves), is then beyond 
doubt. 

Such are the principal characters of the spinal motor nerve- 
cells ; and here seems the place to observe the characteristics 
o{ the pyramidal cells of the gray cortex (Fig. 4). 

These cells are quite variable in dimensions, the most of 
them are relatively very small. The pyramidal cells, which 
may be placed in this class, have at the base a mean diameter 
of O.OIO m. Those of the larger sort, less in number than 
the preceding, generally occupy the lower portion of the 
layer of pyramidal cells. Their diameter attains to 0.022 m. 
(Koschewnikoff). 

Finally there are giant pyramidal cells (Ricsenzcllen). 



THE GRAY SUBSTANCE OF THE BRAIN. 



17 



They have been carefully studied by Betz (of Kiew) and by 
Mierzejewski. They are found in certain well-determined 
regions of the gray cortex. The diameters of these gigantic 
cells sometimes reach 0.040 
m. to 0.050 m. , that is, they 
equal the cells of the ante- 
rior cornua of the spinal 
cord. 

However they may differ 
in dimensions, the essential 
structure of the pyramidal 
cells appears always the 
same. Therefore, for con- 
venience' sake, we will 
study the larger kind, or 
the giant-cells. 

To a certain point the 
term pyramidal cells may 
be used literally ; their form 
resembles, indeed, a more 
or less elongated pyramid. 
The body of the cell re- 
calls the description which 
we have just given, and 
Schultz records that he has 
seen fibre-like structure in 
it. The nucleus, according 
to very many authors, is 
angular, and reproduces in 
a certain degree the gen- 
eral form of the cell. The 
nucleolus itself presents no- 
thing special, 




Fig. 4, — Pyramidal prolongation. 



The cellular prolongations offer peculiarities worthy of in- 
terest. One of them may be Z2\\qA pyramidal prolongations, 
for it is, as it were, the body of the cell progressively nar- 
rowed. As they extend they give off lateral branches, and 
at their extremities they often divide in form of a fork, and 



l8 DISEASES OF THE BRAIN. 

this extremity is always directed towards the surface of the 
convokition. It follows that the cell is situated so that its 
base is parallel to the interior or medullary border of the 
zone of the gray cortex. 

Other prolongations of the same category extend some- 
times from the angles, sometimes from the base, and they 
ramify in such manner as to recall the protoplasmic prolonga- 
tions of the spinal motor cells. Do these prolongations ter- 
minate in a nerve network in the gray cortex, the same as 
Gerlach says occurs with the spinal cells ? Some authors say 
they do. 

There certainly exist for the larger pyramidal cells, for the 
giant-cells, and perhaps for the small cells, cylindrical prolon- 
gations quite analogous to those of the spinal motor cells. 
In both, the origin is a slender filament which soon becomes 
somewhat larger. Upon successful dissections it is possible, 
at a certain distance from the cell, to discover that the pro- 
longations are covered with a cylinder of myeline. Koschew- 
nikofif^ placed this fact beyond doubt by examination of 
cells from the anterior lobes of the brain of one who died 
from encephalitis ; and since the publication of his work the 
reality of his description has often been demonstrated by 
others. These basilar p7 elongations, to use Meynert's expres- 
sion, are always turned towards the medullary substance of 
the convolutions. 

That which we have adduced makes it impossible to misun- 
derstand the analogies associating the pyramidal cells of the 
gray cortex — at least the large cells and the giant-cells — with 
the motor cells of the anterior cornua of the spinal cord ; and 
these analogies (already described by Luys : J. Luys, RecJicrcJies 
sur Ic sysfenie nervetix, etc., p. 162 et suiv., Paris, 1865) we 
must consider later. 



' A. Koschewnikoff. — Axencylinderforsatz der Nervenzellen iin kleinen Him des 
Kalbes. In Schultze's Archiv, p. 332, 1869. AxencylimlerforsUlz der Nervenzel- 
len aus der Grosshirnrinde. Idem, 1S69, p. 375. Betz, Centralblatt. 1874, p. 579 ; 
Mierzejewski, Etudes sur les lesions cerebrales dans la paralysie generate, in 
Archives de pliysiologie, p. 194, 1875. J. Batty Tuke, Morisonian Lectures, in 
Edinb. Med. Journal, p. 394, May, 1874. 



THE GRAY SUBSTANCE OF THE BRAIN. 19 

The pyramidal cells are not the only elements found in the 
gray substance. There are also small globular cells (rarely 
pyramidal), measuring from 0.008 m. to O.oio m. (Meynert),' 
sometimes furnished with small prolongations ; they are 
generally sparse, though sometimes, or at some points, they 
form a tolerably thick layer. Various writers have regarded 
them as incompletely developed nerve-elements ; others again 
have denied them this character, and compare them to the 
elements which constitute the granular layer of the retina. 

Meynert ranks also among the nerve-elements of the corti- 
cal zones a kind of elongated, generally fusiform, ramified 
cell, and which at certain points constitutes a fifth layer. 
These cells generally have their grand axis directed parallel 
with the fibres which connect the convolutions {tJie system 
of association), medullary fibres that run from one convolution 
to another (fibr?e arcuatae) ; the last-named cells seem to 
make a part of that system. 

These, then, are the cellular nerve-elements, so reputed, 
which enter into the structure of the gray substance. Besides 
these, there are other elements which we ought to mention : 
the medullary tubes and the amorpJioiis cerebral substance 
(neuroglia). To these last, which penetrate the gray substance 
as fasciculi, we will return later. As for the neuroglia, still 
known under the name of formation ependymaire (Roki- 
tansky), that serves as an amorphous uniting substance. I 
will not enter into the detail of the peculiarities of structure 
relative to the neuroglia of the gray substance. I will only 
remark that latterly it has been considered by various authors 
as composed of a peculiar kind of conjunctive cells, the bodies 
of which contain very little protoplasm, and are furnished 
with non-ramified prolongations {^cellules araignees de Boll et 
Golgi). These prolongations, entangled and cemented by an 
interposed gelatinous substance, would be considered as com- 
posing the entire mass of neuroglia. We must examine that 
interpretation. Without denying the normal existence, in 
certain regions, of ramifying cells {cellules de Deiters), I will 

' Meynert. — Strieker's Handb., t. II., et traduct. anglaise,lt. II., p. 381 et suiv. 



20 DISEASES OF THE BRAIN. 

remark that the gray substance in that respect is very likely 
fashioned upon the same model as is the white. In other 
words, the neuroglia resembles the type of ordinary conjunc- 
tive tissue, conjunctive fasciculi, and flat cells (Ranvier) ; only 
in the neuroglia the fibrous filaments would be freer than else- 
where. For the present, I omit the study of the vessels ; they 
Avill shortly receive our special attention. 

This suffices, I think, concerning the individual history of 
the various elements which compose the gray substance. 
We should now examine the method in which these elements 
are arranged, in order to see what may be the difference in 
arrangement, as well also as in respect to the constitution of 
the elements themselves, in each of the various regions which 
are divided off by the main fissures on the surface of the brain. 

There is a certain arrangement which may be considered 
as representing the most common type, and it is also the 
most widely extended ; it is the one that in thin slices may 
be distinguished with the microscope, and which presents 
five successive layers. It is met with nearly everywhere in 
the anterior lobes. The elements are separated as follows : 

I. The jfirs^ layer, the one nearest the meninges, is com- 
posed almost exclusively of conjunctive substance. There 
the nerve-elements are very scarce ; Kolliker and Arndt/ 
however, describe a layer near the surface, under the pia 
mater, of very delicate parallel nerve-tubes. The nerve-cells 
in this locality are very sparse. To the naked eye that layer 
has the appearance of a little white zone. The absence of 
color seems due to the poverty of nerve-elements and to the 
small number of capillary vessels contained in the layer. 
Indeed the arterioles penetrating the cortex do not furnish 
numerous capillaries except to the lower layer. That pecu- 
liarity of structure is very well indicated in a plate by Henle,^ 
and in a cut in the niemoire of Duret.^ 

' R. Arndt. — Studien iiber die Architektonick der Grosshirnrinde des Menschen, 
in Arch, fiir mikroskop. Anatomic, 3d Bd. — 1867, p. 441, Taf. xxiii., Fig. i, a, et 
Fig. 2. 

"^ J. Ilenle. — Ilandb. der Nervenlehre, p. 274, Fig. 201, Braunschweig, 1871. 

" Archives de Physiologic, T. vi., pi. 6, Figs. 2 et 3. 



THE GRAY SUBSTANCE OF THE BRAIN. 



21 




X^ T "^ 



I 



r 



2. The second layer (Fig. 
5) is marked by an agglom- 
eration of pyramidal nerve- 
cells of the small species, 
numerous and very close 
together, which give it a 
decided gray color. 

3. The third layer (Fig. 
5) is chiefly composed of 
pyramidal cells, some of 
the medium size and some 
voluminous. The latter, 
more separated from each 
other than the first, are 
generally situated at the 
lower part of the layer, and 
penetrate even into the 
next (fourth) layer. Be- 
sides the cells there are to 
be found in the third layer 
fasciculi of medullary fibres 
which dip perpendicularly 
to the surface of the cor- 
tex, forming as it were col- 
umns between the groups 
of pyramidal cells. This ar- 
rangement has been faith- 
fully represented by Luys ^ 
and by Henle.^ It is in the 
lower portions of the third 
layer that in some regions 
the giant-cells exist. It 
would seem as though the 
rarity of cells and the pres- 
ence of medullarv fibres 'B'sfiT? 
ought to give this layer a 

white appearance ; it really Fig. 5.— Five-layer type of cerebral cor- 
V.-1C- -, ,,^11^.. :„U _ 1 u tex. (Brain of mammalia) — Meynert. 

has a yellowish color, prob- prom strUkers Hand-book. - -- ^ 



T. II., p. 704. 



' Atlas, etc., pi. xx., Fig. 4. 



Loc. cit., Fig. 198, p. 271. 



22 DISEASES OF THE BRAIN. 

ably from the presence of pigment and the abundance of 
capillary vessels. 

4. Then comes \.\\q fourth layer (Fig. 5), where are seen the 
globular cells with ill-determined characters, and the fifth 
layer, where are found the fusiform cells of which we have 
just spoken. 

These summary investigations have enabled us to appre- 
ciate the interest which might result from an examination of 
the structure of the gray cortical substance, made convolu- 
tion by convolution. It has long been known that the differ- 
ent regions of the gray cortex differ notably from each other 
in point of structure. But the most recent and fertile study 
in this direction is by Betz, the results of which have been pub- 
hshed in the Centralblatt of the past year.^ Betz proposes 
examining the modifications of texture of the gray substance, 
convolution by convolution. In this respect he claims that 
on the surfaces of the hemispheres there are two fundamental 
regions which are nearly divided by the fissure of Rolando. 

A^itcrior to that furrow the gray cortex is characterized by 
a predominance of large pyramidal cells over the globular 
cells. The orbital region is included in this division. 

Back of tJie furrow this region embraces all the sphenoidal 
and occipital lobes and the median portion, to the anterior 
border of the quadrilateral lobule. There the granular cells 
preponderate, and the large ones are relatively rare. 

Besides this there is a special department in each of these 
regions which deserves attention. We will deal first with that 
of the posterior region. 

i.st. Here, the well-developed nerve-elements are the toler- 
ably large cells. According to Meynert they were the 
largest found in the cortex of the hemispheres before the dis- 
covery of the girnt-cells. They are sometimes the 0.030 m. 
in diameter. The protoplasmic prolongations are not nu- 
merous ; the basilar prolongations are directed horizontally, 
and sometimes constitute communications between the cells. 



' p. Betz, of Kiew. — Anatomischer Nachweis Zweier Gehirncentra. In Cen- 
tralblatt, 1874, No». 37 et 38. 



THE GRAY SUBSTANCE OF THE BRAIX. 23 

The territory where that character is observed includes (a) 
the cuneiis ; {b) the posterior half of the Hngual and fusiform 
lobules ; {c) all the occipital lobe ; {d) the first two sphenoi- 
dal convolutions and the transition convolution {pli de pas- 
sage). According to Betz, this region is devoted to the 
functions of sensibility. From other reasons of an anatomi- 
cal order, to which we will revert, the posterior parts of the 
brain have for a long time past been spoken of as the seat of 
the sensorium. 

2d. The anterior lobe deserves particular notice, and may 
be called (you will see why) the department of the gia?it 
pyramidal cells, or the motor cells par excellence. This de- 
partment embraces the entire ascending frontal convolution, 
the superior extremity of the ascending parietal convolution, 
together with a part which we will soon study under the 
name of paracentral lobule, and which is situated upon the 
internal face of the hemisphere at the extremity of the as- 
cending convolutions. It is here that exist almost exclusively 
the giant-cells. Their distribution is not uniform, for they 
are more numerous than elsewhere at the superior extremity 
of the two middle convolutions, and above all in the para- 
central lobule. They are located in groups or islands. 
They are to be found in certain points, which will be indi- 
cated, in all species of monkeys, the inferior as well as the 
chimpanzee. Indeed Betz has observed in the dog the 
same kind of cells at those points designated by Fritsch and 
Hitzig as motor centres — otherwise spoken of as the parts 
neighboring the salens cruciatns. Interest is added by the 
fact that in the dog the giant pyramidal cells exist nowhere 
else but in the regions called psycho-motor. It doubtless has 
not escaped your notice that in the monkey the distribution 
of the large nerve-cells very closely corresponds to those con- 
volutions where experiments, in the hands of Ferrier, have 
demonstrated the existence of motor points, namely, in the 
central convolutions. This is an interesting result furnished 
by histological study, and which, combined with experimental 
or anatomico-pathological results, cannot fail to throw some 
light upon the development of cerebral localizations. 



THIRD LECTURE. 

CONSIDERATIONS UPON THE NORMAL STRUCTURE OF 
THE GRAY SUBSTANCE OF THE CONVOLUTIONS. 

(Continuation.) 

Sninmnry : — Description of a Section of tlic Gray Matter of tlie Cere- 
bellum.— Type of tlie Five-Layer Stratifications of Cellular IVcrv-e- 
Eleinents. — Regions wUere tliis Type of Stratification Exists.— De- 
partment of Pyrantidal or Giant-Cells. — Relations bet-ween tlie Cells 
and tlie Psyclio-motor Centres. — Description of the Internal Face of 
tlic Cerebral Hemisplieres. — Paracentral liobnle. — Ascending Convo- 
lutions. — Clinical and Experimental Facts Relative to tlie Develop- 
ment of tlie Pyramidal Giant-Cells. — Structure of the Gray Matter 
in tlie Posterior Regions of tlic Enceplialon. 

Gentlemen : 

Before proceeding further towards the purpose of our 
subject — the theory of locaHzation in cerebral maladies — 
I ought to complete the matter broached in the last lecture, 
relative to the differences in the normal structure of the gray- 
matter, as found in the various convolutions of the cerebral 
hemispheres. 

A. We will first examine the common type, or the one most 
generally and best understood. With Meynert, one may call 
it \\\Q. five- lay C7- type of cellular nerve-elemeiits — so reputed. 

I will briefly recall the characteristic traits of that type. 
To assist in this let us again glance at Fig. 5, a section of the 
third frontal convolution at the base of a fissure. 

As a contrast, we will run over the description of a section 
of the gray substance of the cerebellum ; this description, like 
the preceding one, is borrowed from Meynert. In the 
gray substance of the cerebellum there are, in successive 
order : ist. A thick layer, poor in cellular elements, and 
which receives the protoplasmic prolongations from the nerve- 



NORMAL STRUCTURE OF THE CONVOLUTIONS. 25 

cells of the subjacent layer, 2d. Below this, a layer where 
are found, according to Meynert, fusiform cells and medul- 
lary fibres running parallel to the line of limit. 3d. Still 
lower, the cells of Purkinje, which occupy the superior por- 
tion of a very granular layer ; below all, the medullary sub- 
stance.' 

If you now examine the figure representing the five layers 
of gray substance of the brain proper (cerebrum), you will 
see that the gray substance is not fashioned in all parts of 
the encephalon upon the same model. I shall shortly show 
you the very well-defined though not so strongly marked dif- 
ferences that are apparent according to the diff*erent regions 
examined in the cerebrum ; but first I must return to the five- 
layer type. 

B. The arrangement thus designated exists in all tiae brain 
anterior to the fissure of Rolando, as well also as a little back 
of it, in a portion of the parietal lobes which is indistinctly 
separated from the border of the occipital lobe. We will 
presently see that this type is notably modified in the pos- 
terior part of the encephalon, including, 1st. All the sphe- 
noidal lobe ; 2d. The occipital lobe ; and 3d. The gray matter 
of that portion of the internal face which is circumscribed by 
the posterior extremity of the occipital lobe and by a furrow 
which is the posterior limit of a distinct region, which we will 
shortly describe under the name of the quadrilateral lobule. 

(rt.) For greater clearness it is necessary to revisit a point 
already surveyed ; namely, that in those regions of the hemi- 
spheres occupied exclusively by the five-layer type, there 
exists a department of itself, where the gray structure is dis- 
tinguished by an interesting peculiarity ; which is, the invaria- 
ble presence in those parts of comparatively enormous pyram- 
idal cells, and which, on account of their size, are called ^zVz;//- 
cells. While these cells retain the pyramidal form common 
to the cellular nerve-elements of these regions, they differ 
not only in dimensions, but also by the distinctness of their 
nerve-prolongations and by the development of their proto- 

' Voir aussi Henle, Nervenlehre, etc., Figs. 162, 163 A, 163 B. 



26 



DISEASES OF THE BRAIN. 



plasmic prolongations. This last trait permits their compari- 
son with the motor nerve-cells of the anterior cornua of the 
spinal cord. 

The regions of this important peculiarity are the central 
regions of the external surface of the hemisphere, to wit : 
the ascending frontal convohttion, the ascending parietal con- 
volution, especially at their superior parts, and finally in a 
little lobule situated upon the internal face of the hemisphere, 
until recently unnamed, and which Betz has proposed to call 
\.\\c paracentral lobicle, (Fig. 6.) 

Sup. extremit}! cf fiss. of Solandov 
Toransverse furrow of paracentral lob-iilc' 

Inl.faceof first 
•frdnlal convolution . 




Wehge. or cvmeiform lobule.' 
Gjrtis ^incinatus. . . \ \ \ Occiptallobe.! 

Ant.^exLpDrliDnof Cms Cerebri 'Cdidlyof.latei-alveritncle- 
Choroid plexus. 

Fig. 6. — Internal surface of right hemisphere of a human brain. {Drawn from 
nature.) ' 

I would remind you that the existence of the giant-cells in 
the gray matter, and their localization in the regions above 
indicated, were discovered by Betz and Mierzejewski. The 
results obtained by these authors have recently been con- 



' Respecting the topography of the median face of the cerebrum, consult pi. 
viii. of Foville's Atlas, and Fig. 4 of Ecker's work. 



NORMAL STRUCTURE OF THE CONVOLUTIONS. 2/ 

firmed by J. Batty Tuke in his lectures at Edinburgh.^ I 
have myself also verified the same. 

I again remind you that the regions remarkable for this 
peculiarity of structure are precisely those where, in the 
monkey, according to Ferrier,* the psycho-motor centres of 
the limbs are located. Is not that a coincidence worthy of 
your attention ? Let us recall the fact also that, in the dog, 
those parts reputed, through the experiments of Ferrier and 
by the previous ones of Hitzig, as excito-motor, are said by 
Betz to be distinguished by the presence of giant pyramidal 
cells — cells which in these animals are to be found in no other 
part of the gray matter. I think my persistence justified by 
the necessity of fixing in your minds as exactly as possible all 
these details. 

{b.) These facts give a very special interest to those regions 
of the hemispheres which possess this anatomical peculiarity. 
I therefore feel that a thorough topographic knowledge of 
those regions is of the utmost use in order to be able to indi- 
cate them with precision in the records of autopsies, and con- 
sequently I will enter this subject more fully. In so doing 
we shall of course have occasion to describe the configuration 
of the middle faces of the hemispheres, a region which up 
to the present time, in my opinion, has remained too little 
known. 

The arrangement of the ascending convolutions, their ori- 
gin at the superior border of the hemispheres, are now so 
familiar to us that our attention can be turned to the arrange- 
ment of the internal or median faces of the hemispheres. In 
that section (Fig. 6) which divides the corpus callosum antero- 
posteriorly you first see at the centre the divided surface 
of the grand commissure ; below, the septum liccidiiin, the in- 
ternal face of the thalamus opticus, then the cut surfaces of the 
crura cerebri. 

Better to obtain our points of compass, we will start from a 

1 Edinburgh Med. Jour., Nov., 1874, p. 394. 

'^ West Riding Asylum, t. IV., pp. 49 and 50, Proceedings of the Royal Society, 
No. 151, 1874. British Medical Journal, Dec. 19, 1874. 



28 DISEASES OF THE BRAIN. 

familiar landmark upon the external face of the brain, that is, 
the fissure of Rolando, and follow it to its extreme internal 
end. This furrow sometimes stops a little short of the inter- 
hemispheric fissure ; at other times it extends quite to it, 
making a sort of notch on its superior border. 

The paracentral lobule is located immediately below that 
point. It is bounded as follows : posteriorly, by an oblique 
fissure, which is the posterior prolongation of the calloso-mar- 
ginal (that fissure extended constitutes the posterior border 
of the ascending parietal convolution) ; beloiu, by that horizon- 
tal portion of the calloso-marginal fissure which separates it 
from the convolution of the corpus callosum (called gyrus 
fornicaiiis) ; anteriorly, by a fissure generally shallow, but 
which sometimes continues upon the internal face of the hemi- 
spheres and which anteriorly marks the internal part of the 
ascending frontal convolution and bounds the anterior face of 
the paracentral lobule. 

Thus we have a small quadrilateral lobule whose greatest 
diameter is antero-posterior. Generally a shallow furrow, 
midway between the upper and lower borders, runs the entire 
length of the lobule. By reason of its structure, as much as 
from its position, it may be said that the paracentral lobule 
seems to represent upon the median face of the hemisphere 
the inverse surfaces, the internal extremities of the two ascend- 
ing convolutions. 

This point fixed, it is not difficult to give the remaining 
topography of the internal face of the hemispheres. 1st. 
Anterior to the paracentral lobule is seen the median surface 
of the first frontal convolution. 2d. Below, and separated 
from the preceding by the calloso-marginal furrow, is the 
convolution of the corpus cdXlozuva {gyrus fornieatus). 3d. 
The last-named convolution is continued posteriorly, forming a 
lobule quite circumscribed, and which is called the quadrilat- 
eral lobule {avant coin, Vorzivickel, prcscuneus). This lobule 
we may consider as the internal or median face of the su- 
perior parietal lobule. Behind tJiis the tcviporo-oceipital fis- 
sure {vQiy marked at this point, because it is not interrupted, 
as upon its external face, by overlying convolutions) separates 



NORMAL STRUCTURE OF THE CONVOLUTIONS. 29 

very clearly the quadrilateral lobule from the occipital lobe. 
4th. Immediately behind the quadrilateral lobule in the 
region of the occipital lobe, there is a triangular lobule, the 
point of which is inferio-anterior, the base posterio-superior, 
and which is bounded posteriorly by a deep fissure, the^ssura 
calcariiia ; that little lobule is called the cinieiis {coin, 
zwickel). 5th. Below that triangle you observe the lack of 
demarcation already noticed upon the external surface be- 
tween the occipito-sphenoidal lobes. In this region should 
be specially observed two convolutions running antero-pos- 
teriorly. They are : (a) the lateral occipito-sphenoidal lobule 
{lobiiliis fiisifonnis) ; {b) the median occipito-sphenoidal 
lobule {lobiiliis Imgualis). 6th. Still in front, and fully within 
the sphenoidal lobe, is the gyrus hippocampi, the hook 
{crochet) which constitutes part of the horn of Amnion {cornn 
Ammonis). 

As we proceed we shall most certainly have occasion to 
use the topographical knowledge which we are obtaining, and 
I hasten to complete the description, which in some respects 
is a digression. 

C. I therefore return to the paracentral lobule and to the 
ascending convolutions. These have already a history in 
experimental pathology, and further on it will be shown that 
they have also a history in human pathology. I am not 
aware whether with the monkey, at least with the higher 
grade of monkey, the paracentral lobule (which exists as with 
man) has ever been the object of physiological investigations. 

(«.) I may here cite a case, unique of its kind to be sure, 
but which nevertheless will for the future lend an interest 
to this lobule as connected with human pathology. This 
instance, of which I give an outline, has been recorded by an 
attentive observer, Sander.^ 

A child who died at the age of fifteen had been attacked in 
the third year of its age with infantile spinal paralysis. The 
malady had included and more or less atrophied all the limbs, 
and especially those of the left side. Autopsy revealed in 

' Centralblatt, 1875. 



30 DISEASES OF THE BRAIN. 

the spinal cord all the lesions described by the French authors. 
A minute examination of the brain led to the discovery that 
the two ascending convolutions upon the external face were 
very much shorter than normal. They left the island of Reil 
somewhat uncovered, besides which they were destitute of 
folds. The paracentral lobule was entirely rudimentary, in 
this respect markedly in contrast with all the other convolu- 
tions, which were perfectly developed. Lastly, the lesions 
were most pronounced in the right hemisphere, which is in 
keeping with the circumstance that the spinal lesions were 
most marked upon the left side. 

The author expresses the opinion that in this case the limbs 
having, at an early age, suffered complete paralysis, resulting 
from a profound spinal lesion, the psycho-motor centres, 
struck with inertia at a time when they were in process of 
evolution, had in consequence been arrested in development. 
The interpretation seems worthy of consideration. It is much 
to be regretted that the condition of the nerve-cells in the 
psycho-motor centres was not ascertained. 

A case observed by Luys to a certain extent resembles the 
foregoing. In a subject where amputation had been made, 
some years previous to autopsy, my colleague at la Salpe- 
trierc noted an atrophy of the cerebral convolution on the 
side opposite to the amputation. Unfortunately the exact seat 
of the atrophy was not (to my knowledge, at least) given. 

{p.) I am thus led to introduce another fact concerning that 
part of the brain with which we are occupied. According to 
the researches of Betz, the giant pyramidal cells exist but in 
small number with very young infants ; it is only later that 
their number increases, and that increase is effected, accord- 
ing to all appearances, under the influence of functional 
exercise. 

This fact is worthy of being joined, on the one hand, with 
that of Sander's, and on the other hand to an observation of 
an experimental order recently recorded by Soltmann.^ That 
author (and I believe that Professor Rouget, of Montpellier, 

' Reizbarkeit der Grosshirnrinde, in Centralblatt, 1875, No. 14. 



NORMAL STRUCTURE OF THE CONVOLUTIONS. 3 1 

has recorded something similar) has observed that with newly 
born dogs the excitation of regions corresponding to the psy- 
cho-motor points produces no muscular movement in the 
corresponding limbs, whereas, sometime afterbirth, towards 
the ninth or eleventh days, these points become excitable. 

These observations, though yet few, should nevertheless 
be taken into account, and they would seem to indicate that 
the psycho-motor centres arc not pre-established, if one can 
so speak, so much anatomically as they are physiologically. 
They are developed by age, doubtless through functional 
exercise. 

In support of this view I offer a remark with which I will 
terminate the special subject that has detained us. The 
regions of the large cells belong to the five-layer type, and 
these regions have no definite anatomical characteristic except 
the presence of giant-cells. Now these giant-cells, morpho- 
logically, do not differ essentially from the large pyramidal 
cells, which also, according to the researches of Koschewnikoff, 
possess, like them, the nerve-prolongations in addition to the 
protoplasmic prolongations, attributed to motor cells. 

It seems natural to inquire if these cells, and even those of 
the smaller species, which are their miniature representatives, 
would not be capable, under certain conditions — under the 
influence, for example, of abnormal functional excitement — of 
acquiring development, and in that way giving birth to sup- 
plementary motor centres destined to replace primitive cen- 
tres that by some lesion may have been destroyed. Thus, 
for example, might be explained how voluntary movements 
can be restored in a part, notwithstanding the destruction of 
a motor centre — a phenomenon, an example of which is fur- 
nished in the frequent recovery from aphasia, in despite of 
the persistence of the lesion of the third frontal convolution. 

D. To complete the examination of the cerebral cortex, I 
have but to add some little information upon its peculiarities 
in the posterior region of the brain. 

These peculiarities belong to the entire occipital lobe, the 
sphenoidal lobe, and the posterior and median parts of the 
hemisphere to the posterior border of the quadrilateral lobule. 



32 DISEASES OF THE BRAIN. 

The general character of the gray substance in those regions 
is that the pyramidal nerve-cells, as a rule, are very scarce 
and small, while the granular, on the contrary, are notably 
predominant. It is not that there are no large nerve-cells, 
but they are comparatively rare — solitary, to employ the ex- 
pression of Meynert. Betz adds that they have no nerve- 
prolongations, and that even the protoplasmic prolongations 
are scarcely developed. 

The portion of the brain where this peculiarity is to be 
observed corresponds, according to many authors, to the sen- 
soriuni coiiumtne. If this interpretation be correct, it would 
follow that the cells of which we are about to speak are cells 
of sensation. This hypothesis rests upon still other anatom- 
ical considerations, and upon pathological evidence of which 
I will hereafter s:ive more detail. 



FOURTH LECTURE. 

PARALLEL BETWEEN SPINAL AND CEREBRAL LESIONS. ' 

Sammary : — The Indispensable Conditions for the Study of Cerebral 
Laocalization in Diseases in Man. — Xecessity of Good Clinical Observa- 
tions and Regular Autopsy. — Natural History of Eneephalic Lesions. 
— Parallel between the Grand Compartments of the Cerebi-o-spinal 
Axis. — Systemization of Iiesions in the Spinal Cord. — Spinal Ijoealiza- 
tions. — The Brain is placed under a Pathological Regime Differing 
from otiier Parts of the IVerve-Axis; Rarity of Localizations. — Differ- 
ence of Lesions. — Frequency of Vascular Lesions in Maladies of the 
Brain. — iVecessity of the Study of Vascular Distribution. — Outline of 
the Cerebral Arteries. 

Gentlemen : 

From the preceding lectures you comprehend that, unpre- 
pared by a precise knowledge of normal anatomy, it would be 
useless to undertake this subject. 

The subordination of pathological to normal anatomy is 
most especially obvious in all questions related to cerebral 
pathology. This will directly be rendered still more evident. 

I. To-day we will commence by recounting the indispensa- 
ble conditions for solving the problems connected with local- 
ization in cerebral diseases, as exhibited in man. 

The following are the fundamental ones : 1st. A good clin- 
ical observation made with the most complete possible knowl- 
edge of existing facts in experimental physiology. 2d. A 
regular, anatomically precise autopsy. 

Our preceding topographical studies make an important 
step, for they will better enable us to determine the locations, 
extent, and configuration of lesions revealed by autopsy. 

For the special object which we have in view, however, 
even the most minute and exact anatomical observations can- 
3 



34 DISEASES OF THE BRAIN. 

not always be utilized. Here as elsewhere, it is necessary 
that observation should teach us how to select from things 
seen, and in this process more than one difficulty must be 
overcome. 

To make you familiar with the situation it is best first to 
survey the nat?iral history of encephalic lesions. 

I St. What are the alterations capable of affecting the en- 
cephalon, or especially the brain? We are now, of course, 
dealing only with the most usual forms of cerebral disease — 
with partial or circumscribed lesions as they are called ; such 
only can be profitably considered in this connection. 

2d. In the second place, what are the general anatomical 
conditions which preside either at the development, or dur- 
ing the process of reparation of such lesions ? For there is 
no chance work, even in the encephalon. 

To accomplish our end I propose once more to employ the 
comparative method, that lever so powerful in natural sci- 
ences. I will make, pathologico-anatomically, a comparison 
between the grand cerebro-spinal compartments (or if you 
choose Piorry's nomenclature, nerve-axis) ; that is : ist, the 
spinal cord ; 2d, the rachidian bulb ; 3d, the brain proper. 

A. It may be said that the pathological physiology of the 
spinal cord is distinguished by the extensive existence in it 
of those lesions called systemic. By this expression, bor- 
rowed from Vulpian, arc meant those lesions which are sys- 
temically (the term is perfectly appropriate) circumscribed, 
and which do not overstep the limits of certain clearly deter- 
mined regions in that complex organ. I beg to refer you to 
figure No. 21, which will recall our past lectures. 

You remember that there are lesions limited to the anterior 
cornua of the gray substance (Fig. 7). They are, in acute 
form, infantile paralysis ; in chronic form, the various kinds 
of progressive locomotor ataxia. There are other lesions 
limited to the lateral fasciculi and which are distinguished by 
symptoms of numbness (paresie) with a tendency to contrac- 
tions. You know that the fibres of Goll may alone be sub- 
ject to lesions ; and that the regions of the little external bands 
(F'ig. 7) {^posterior columns) in the area of the lateral fasciculi 



SPINAL AND CEREBRAL LESIONS. 



35 



is the only anatomical snbstj-atiim necessary for symptoms 
of spinal tabes. 

It is thus that pathological anatomy, guided in its first steps 
by experiment with animals, and aided also by clinical ex- 
perience, has become able to separate, in man, the complex 
organ called the spinal cord, into a certain number of com- 
partments, departments, and secondary organs. 




Post^. Cornu.< 



bsl.Comu* 



/fibers of Goll. 

Fig. 7. — Transverse section of spinal cord. 



To each systemic lesion of these various regions belong 
groups of symptoms or syndromes which clinically serve to 
individualize them, and which have also given place, in path- 
ological descriptions of the spinal cord, to a certain number 
of elementary affections. Analysis, founded upon a knowl- 
edge of the elementary affections, is a great help in unveiling 
mixed or complex forms. 

The study of these systemic lesions has doubtless contrib- 
uted greatly to rescue spinal localization from its past chaos. 

B. Systemic lesions are found extended to the racJiidian 
bulb, \hQ protnberajice, and the crura cerebri. I will cite for 
examples the secondary degenerations of the cord consecutive 
to lesions of the brain, primitive and symmetrical sclerosis of 



36 DISEASES OF THE BRAIN. 

the lateral colinnn, bulbous paralysis from exclusive lesion 
of the ganglia at the origin of the nerves, etc. But above 
that point this mode of pathological alteration does not ap- 
pear to exist, and it may be said that to the present systemic 
lesions in the brain are unknown. 

No one really knows of systemic lesions limited to the 
thalami optici, to the different ganglia of the corpora striata, 
or to the various portions of the cortex. It does not follow, 
however, that strict research cannot determine anatomical 
localizations in the encephalon, but they are at present rela- 
tively rare, and seemingly accidental. 

What is the real reason of this singular fact ? It is that the 
encepJialon is placed under tx pathological regime, so to speak, 
differing from that controlling otJicr portions of the nerve- 
axis. In fact, speaking in a general way, in the encephalon, 
and especially in the brain, the vascular system (arteries, 
veins, and capillaries) commands the situation. 

I will call attention to the importance of vascular ruptures 
and ensuing hemorrhage in the intra-encephalic centres ; 
the predominant role of vascular obliterations by thromboses 
and emboli, the effect of which is extravasation followed by 
partial softening of the brain. 

I will enumerate the most common anatomical causes of 
organic disease in the encephalon. 

C. If we now return to the spinal cord and bulb, we will 
observe a remarkable contrast to the encephalon. Hemor- 
rhage by vascular rupture, whether resulting from the altera- 
tion well known under the name of miliary aneurism, from 
softening consecutive to arterial narrowing, or from throm- 
bosis or embolism, is something which in the spinal cord is 
almost unknown. 

The bulb constitutes, as it were, the transition between the 
spinal cord and the encephalon, for in the bulb is seen, on 
\):iQ oViO. \\7i.xii\, systemic lesions \y\i\c\\ recall those seen in the 
cord, and on the other hand, a certain number of hemor- 
rhages and softenings are found resulting from vascular 
lesions. 

These last, however, are still more frequent in theprotubc- 



SPINAL AND CEREBRAL LESIONS. 3/ 

ranee, the pathology of which also approaches more nearly 
that of the encephalon. Hemorrhage from rupture of mili- 
ary aneurism, and softening by vascular obliteration, here 
become frequent. 

D. These considerations explain why the most common 
anatomical localization in the encephalon is to be arrived at 
chiefly through a knowledge of the vascular distribution ; 
for the broken vessel being known, one can, as Lepine has 
truly said, decide the outline and extent of the territory 
involved. 

This directs us once more to the field of normal anatomy, 
for the purpose of obtaining some general ideas relative to the 
vascularization of the encephalon. This is a subject worthy 
of your entire attention, the more so that the questions relat- 
ing thereto have been thoroughly investigated, and to this 
your countrymen have contributed their share. 

11. For the present it will suffice to examine the arterial 
system, although lesions of the venous system have also a 
marked influence upon the development of encephalic altera- 
tions. The immediate object is to show by some examples 
how important a profound knowledge of the normal conditions 
of cerebral circulation is to the understanding of the majority 
of anatomical lesions of the brain. 

You remember the manner in which the trunks of the two 
internal carotids and the two vertebral arteries join at the 
base of the encephalon to carry on the circulation.^ 

The internal carotids, as they leave the cavernous sinus, run 

' It is known that hemorrhage and softening of the brain are much more fre- 
quent on the left than on the right side. Duret, in his nuhnoire, thinks to have 
discovered the anatomical solution of this fact in the manner in which the primitive 
carotid and the vertebral arteries of the left side originate. The right carotid 
arises from the innominate, and the iimominate, at a considerable angle, from the 
axis of the aorta, whereas the left carotid ascends nearly perpendicularly, and its axis 
is more nearly continuous with the ascending aorta. It follows that a clot expelled 
by a cardiac contraction would, by a direct line, be more apt to enter the left carotid. 
The right vertebral arteiy rises from the horizontal portion of the subclavian 
after it has made its curve ; the left vertebral artery, on the contrary, takes its rise 
from the summit of the curve of the subclavian. 



38 



DISEASES OF THE BRAIN. 



perpendicularly to the base of the brain, and immediately 
divide into two branches, the one anterior (the anterior cere- 
bral), the other, running laterally, bears the name of Sylvian, 
or middle cerebral artery (Fig. 8). Near their origin the two 
anterior cerebral arteries are transversely united, and thus, in 
a more or less complete manner, the circulation of the two 
internal carotids are unified. That vascular arrangement con- 




Vertel). Arteries. 
[ P"iG. 8. — Scheme of arterial circulation at the base of the encephalon. 



stitutes a special system, to which may be given the name of 
anterior system, or carotid system. 

The vertebral arteries, directed obliquely from behind for- 
ward, converge towards the median line and unite in a single 
trunk, the basilar trunk. Towards the anterior border of the 
protuberance, this basilar trunk separates into two branches, 



SPINAL AND CEREBRAL LESIONS. 39 

called the posterior cerebral arteries, and these constitute a 
second arterial system, the posterior, or vertebral system. 

The carotid system and the vertebral syston, united by two 
vessels called the posterior communicants, and which arc quite 
variable in volume and arrangement,' form a vascular circle 
at the base of the brain, known to all anatomists under the 
name of the hexagonal, or better, \\\q. polygon of Willis. 

At the anterior angles of the polygon of Willis are the two 
anterior cerebral arteries ; from the antero-lateral angles, 
running outwards, arise the two Sylvian (middle cerebral) 
arteries, and finally, the posterior angle is formed by the 
posterior cerebral arteries. This is the circle of Willis, and the 
first two centimetres of those various arterial trunks give rise 
to the nutrient arteries of the central ganglia, the corpora 
striata and thalami optici. 

There are six principal groups of these nutrient arteries. 

The first — antcro-median group — has its origin in the ante- 
rior communicant and in the commencement of the anterior 
cerebral arteries. The arterioles of which it is composed 
nourish the anterior part of the head of the caudated ganglion. 

The second — postero-mediaji group — arises from the pos- 
terior half of the posterior communicants, and from the origin 
of the posterior cerebral arteries. They nourish the internal 
face of the thalami optici and the walls of the third ventricle. 

The third and fourth — riglit and left antero-lateral groups 
— composed of a larger number of arterioles, rise from the 
Sylvian arteries and supply the corpora striata and the ante- 
rior part of the thalami optici. 

The fifth and sixth — postero-lateral groups — are derived 
from the posterior cerebral arteries after they have passed 
around the crura cerebri ; they nourish a great part of the 
thalami optici. 

Aline surrounding the circle of Willis, two centimetres out- 

' Duret has directed attention to the frequent variations and anomalies of the 
circle of Willis and the communicants. These last are often filiform and entirely 
insufficient to re-establish circulation in case of obliterations. Certain forms of 
anomalies explain also cases of softeningof an entire hemisphere, by a clot obliter- 
ating the internal carotid near its bifurcation. 



40 DISEASES OF THE BRAIN. 

side of it, would include the origin of \\\q ganglionic arteries, 
and it might also be termed "Cixo. ganglio7iic circle (Fig. 8). 

The cortical regions (the convolutions of the cerebral hemi- 
spheres) are irrigated by the large arteries which form the 
angles and sides of the circle of Willis. 

The anterior cerebral artery winds around the corpus cal- 
losum, and spreads upon a portion of the inferior face of the 
anterior or frontal lobe {gyms rectus and gyri supra-orbitales^ 
and over a larger portion of the internal face of the hemi- 
sphere {first and second frontal convolutions ^ prcecentral and 
quadrilateral or pr<£cuneus lobules.) 

The posterior cerebral artery, springing from the basilar, 
winds around the corresponding cerebral peduncle, and divides 
into three branches, which go to the inferior face of the brain 
and to the occipital lobe {gyms tincijiatus ; gyms Jiippo- 
campi ; second, tJiird and fourth temporal convolutions ; the 
cuneus ; lobulus lingualis). 

The Sylvian (middle cerebral) artery is distributed to that 
part of the frontal lobe which is not vascularized by the 
anterior cerebral artery, and over the entire parietal lobe. 
Later it will be necessary to follow in detail the distribution 
of each of the four branches of this important artery, and to 
describe exactly their vascular territories. 

Such, then, is the general distribution of the arteries sent 
to the internal, external, and inferior faces of the brain. To 
understand the interior vascular arrangement it is necessary 
to have recourse to various sections. Upon a single section 
made within the domain of the Sylvian artery, the circulation 
in the gray ganglia will seem to be confounded with that of 
the surrounding gray matter and the subjacent white ganglia ; 
that is but an illusion, however, which will be dispelled in 
the next lecture. 



I 



FIFTH AND SIXTH LECTURES. 

ARTERIAL CIRCULATION IN THE BRAIN. 

Summary: — I^abors of Durct ami Henbncr. — Principal Arteries of tUe 
Brain. — The System of Cortical Arteries. — Nutrient Vessels. — System 
of the Central Arteries, or of tlie Central Ganglia. — Sylvian Artery; 
Its Branches; Arteries of the Central Gray Ganglia; Cortical 
Branches; Ramifications and Arborizations; Nutrient Arteries of 
the E}nceph:tlic Pulp; they are Long (Medullary Arteries) and Short 
(Cortical Arteries). — Effects of Obliterations of the Various Arteries. 
— Superficial Softenings, Vello-w Spots. — Communication between the 
Vascular Territories; Opinion of Heubner; Opinion ofr>uret. — Ter- 
minal Arteries (Cohnheim). — Relative Autonomy of the Vascular 
Territories of the Brain. — Localizations of Cortical Lesions. — Branch- 
es of the Sylvian Artery ; Frontal, External, and Inferior.— Artery of 
the Ascending Frontal Convolution, — Artery of the Ascending Parie- 
tal Convolution. — Artery of the Gyrus Angularis.— Anterior and Pos- 
terior Cerebral Arteries ; their Branches. 

Gentlemen : 

To-day I propose to examine more thoroughly the subject 
which was barely introduced in our last lecture. If I have 
clearly shown that in cerebral pathology it is the arterial 
system which commands the situation, I must, as a matter 
of course, through the same effort, have proved the necessity 
of preliminary studies concerning the physiological connec- 
tion between the circulation and the various departments that 
compose the brain proper. 

How, indeed, can one comprehend the rationale of hemor- 
rhagic centres, or centres of softening, which constitute the 
chief pathological anatomy of the brain, if he is not entirely 
familiar with the special distribution of the arterial vessels, 
an alteration in which is the commencement or the first con- 
dition of these various lesions. 

Unapplied facts in normal anatomy will not here suffice. 
But the application of them at once suggests itself. I have 



42 DISEASES OF THE BRAIN. 

already shown this, and I shall now exhibit it still more 
clearly. 

I pause at this point in the anatomy of cerebral circu- 
lation, because that, even in the works most justly esteemed, 
you will find on this subject only the most vague and en- 
tirely insufficient information, quite inadequate to our needs. 

All the precise knowledge which we have is of recent date, 
and is the result of studies exacted through the needs of 
pathological anatomy and physiology, 

I shall borrow particularly from the important work of our 
countryman, Duret — a work which has been executed in the 
laboratory of Salpotriere. Duret has encountered a rival in 
his field. That rival is a German doctor, Heubner, professor 
at the Leipzig University. These two authors, unacquainted 
with each other, have pursued their researches simultaneously, 
and in the most essential points they have arrived at identi- 
cal results. That assuredly is a guarantee of the exactness 
of the descriptions which they have given us. 

In a recent work treating of syphilitic alterations in the 
cerebral arteries,^ Heubner professes to have been the initia- 
tor. That is a claim which cannot be sustained. The first 
researches of Duret relative to the circulation in the bulb and 
the protuberance were communicated to the Societe de Bio- 
logic in the session of Dec. 7, 1872. 

By a remarkable coincidence, the same day, the 7th of 
December, the resume of the researches of Heubner upon 
cerebral circulation was published at Berlin in the Ceiitral- 
blatt. One month after, in January, 1873, Duret published 
a note in the Progres medical'^ concerning that part of his 
researches which treated also of the cerebral circulation. The 
investigations of Duret are not, then, two years later than 
those of Heubner, as the latter insinuates ; they are exactly 
contemporaneous. Of this fact Heubner might easily have 
convinced himself, as he has become acquainted with the last 
memoire of Duret, published in the Archives de pJiysiolo- 



' Die luetische Erkrankung der Hirnarterien, p. i8S, Leipzig, 1S74. 

' i8th and 25th of January, ist of February, 8tli and 15th of November, 1873. 



ARTERIAL CIRCULATION IN THE BRAIN. 43 

gie (1874), where the history of the question is given in de- 
tail.^ 

I have thought it well to insist upon this chronology, in 
face of the annexation mania, in order to establish the large 
part which belongs to our countryman. 

I. I come to the special object of our studies. You know 
the manner in which the three trunks, rising from the circle 
of Willis, divide among themselves the arterial circulation in 
each cerebral hemisphere. They are : ist, the anterior cere- 
bral ; 2d, the middle cerebral or Sylvian artery, each rising 
from the internal carotid ; 3d, the posterior cerebral, branches 
from the basilar, a single trunk formed by the confluence of 
the two vertebral arteries. 

A. Each one of these arteries, in each hemisphere, com- 
mands a special province ; I have already briefly acquainted 
you with the general topography and limits of these main 
vascular territories, and they should be examined not only 
at the surface of the hemispheres, but also, by aid of sections, 
in their interiors. 

Our attention should first be given to the surface of the 
brain, including the external, superior, internal, and inferior 
faces, and secondly to frontal sections, which will demon- 
strate the preponderating importance of the Sylvian territory. 

We will soon see that these territories or provinces can be 
divided into a certain number of secondary departments, 
corresponding to the distribution of so many secondary ar- 
teries emanating from the principal trunks. 

B. Without stopping longer at this first general view, we 
will enter at once into details. Each one of the three prin- 
cipal arteries gives rise to two very diflerent systems of secon- 
dary vessels. The first of these may be denominated the 
system of cortical arteries. The vessels of which it is com- 

' The researches of Duret possess a considerable pathological interest, for they 
have been made especially to explain the appearance of lesions found in autopsies. 
With the aid of more than two hundred cases furnished him by Charcot, he has 
been able to establish an anatomical classification of cerebral hemorrhages and 
softenings. 



44 DISEASES OF THE BRAIN. 

posed are spread through the pia mater, and there divide, 
after a pecuHar method, before furnishing the little vessels 
which penetrate the cerebral pulp, and which are really the 
mitrient vessels of the gray matter and the subjacent medul- 
lary substance. 

The second system is the central system, or the system of 
the cerebral ganglia {gray central masses). The vessels of 
which it is composed rise from each of the three principal 
arteries close to their origin, and, in the form of arterioles, 
plunge immediately into the substance of the ganglionic 
masses. 

The tivo systems, although they have a comnion origin, are 
entirely independent of each other, and at the border of their 
domains they have no point of i^ttercommnnication. 

C. We must study the two systems in each of the main 
vascular territories. In doing this we will observe both com- 
mon and special traits. We will first examine the Sylvian 
artery, the most important and the most complicated of the 
three cerebral arteries ; after that the description of the two 
others will be simple. 

II. The Sylvian artery enters the fissure of Sylvius, the lips 
of which must be separated in order to bring the vessel well 
in view. But before this it furnishes from its superior border, 
in a region called the anterior perforated space {locus perfo- 
ratns anticiis), a series of arteries which, running parallel to 
each other, enter each of the channels of the perforated space, 
which space is composed of the white substance {substantia 
perforata). These are the arteries of the central gray ganglia, 
or more definitely, tJie arteries of the corpora striata. Let 
us here examine the cortical system, leaving for the moment 
the gray ganglia. 

At the bottom of the fissure of Sylvius is seen the island 
of Reil, on a level with which the Sylvian artery divides into 
four branches, each of which deserves a special name. These 
branches follow the furrows that separate the convolutions of 
the island and to which they furnish vessels. They then bend 
inwards and outwards, and rise again to the surface of the 



ARTERIAL CIRCULATION IN THE BRAIN. 



45 



hemisphere, where they are distributed, as we have just said, 
over a certain number of fundamental convolutions, where 
they form a number of little secondary territories correspond- 
ing to each one of the convolutions. (Fig. 9.) 

£"■ £-orrIal convol?, , A.SCending frontal convolution 

>3 ■ fronial c(?rLvo!ul{on . j <5^ 

,1^} frontal convo(luiion ^ 

I Ascen(jing jpanetal conyol". j^pT paj-i'efal lotuTe . 



(3 




Truni; of.-l 
Sjlviaoi artery 

Ext. ^infr. frontal brandh P^_j_--i',r) , -, ■■,■,„ , ■, , 

Ascending frontal artery,! j vPanelo- sphenoidal S. spher.oidal artenes 
LA.scending' parietal artery 

Fig. 9. — Distribution of Sylvian artery. (Pa7-tiaUy schematic.) 

We will not dwell, however, upon this description, but pro- 
ceed to examine more thoroughly the manner in which the 
cortical arteries are divided and distributed to the substance 
of the pia mater before they penetrate the cerebral pulp. 

I should mention that the branches arising from the Sylvi- 
an artery immediately subdivide into branches of the third 
order, to the number of two or three for each secondary 
trunk. These tertiary branchlets constitute a kind of vascu- 
lar skeleton, upon which is grafted a system oi arborizations ; 
that is a special and very original system of small vessels, 
which arise not only from the extremities of the branches, but 
also from the trunks themselves. 



46 DISEASES OF THE BRAIN. 

Contrary to the assertions of most authors, Duret affirms 
that these arborizations do not anastomose with each other, 
although the branchlets sometimes communicate with those 
of the neighboring territories. (Fig. lO.) 



Nelwor"k- of 

cortical arterie: 
Cerebral pulpi 




Medullary 

braucEes' 



Fig. io. — Arterial division in the encephnlon. {Durct.) 

The ramifications and arborizations are on a plane with 
the pia mater. On the internal face of that membrane they 
give off the nutrient arteries, which enter the encephalic pulp 
perpendicularly. The nutrient vessels here are all, according 
to the definition of Ch. Robin, capillaries. This character 
distinguishes them from the vessels of the central ganglia, 
which bury themselves in the white substance of the base of 
the brain (anterior perforated space), inasmuch as these last 
retain the structure and dimensions of arteries. 

By aid of sections which can be examined microscopically, 
we will now investigate more closely the peculiarities of these 
mitrient arteries. 

Upon section of an entire convolution, made perpendicu- 
larly to the surface, there appears, first at the periphery, the 
gray substance which is like a festoon, having a thickness of 



ARTERIAL CIRCULATION IN THE BRAIN. 47 

two or three millimetres ; next to this is the medullary sub- 
stance composed of diverging and commissural fibres, binding 
one convolution to another. In such sections what is found 
to be the arrangement of the arteries ? There can easily be 
distinguished two kinds of nutrient arteries which have long 
since been recognized by many authors, and particularly by 
Todd and Bowman. Of these arteries one kind are long and 
the other short. 

1st. The long arteries, otherwise called the medullary ar- 
teries, arise from the raniifications, or indeed are the terminals 
of the arborisations. A dozen or fifteen may be seen upon 
a section of a convolution ; three or four at the free surface ; 
the others distributed upon the two slopes or in the separating 
furrow. The arteries at the summit are vertical — one of them 
generally occupies the middle part of the convolution ; the 
arteries on the slope are oblique ; those which occupy the 
bottom of the furrow are again vertical. These arteries pene- 
trate the centrum ovale to the depth of three or four centi- 
metres ; they proceed without intercommunicating, except by 
means of fine capillaries, and in that way constitute so many 
little independent systems. At their terminations they ap- 
proach the extremities of the central system of arteries, but 
there is no coniviunication whatever betzveen the two systems. 

Thus there exists upon the confines of the two domains a 
sort of neutral ground where nutrition is less active. This 
neutral ground is more especially the location of lacunal senile 
softenings. 

2d. The sliort nutrient or cortical arteries have the same 
origin as the long ones, but they are finer and shorter, and 
end, so to speak, on the road. Some run to the inner border 
of the gray layer, to the edge of the medullary centre ; others 
are of less extent, and terminate in the gray substance. These 
short arteries give rise to capillary vessels which, conjoined 
with those emanating from the long arteries, form a mesh or 
web. 

In the convolutions this network possesses the following 
characters (Fig. 11): ist. The first layer has the thickness 
of a half millimetre ; it is but slightly vascularized ; 2d. The 



48 



DISEASES OF THE BRAIN. 



second layer corresponds to two zones of nerve-cells ; there 
the vascular network is very compact, and with very fine 
polygonal interspaces ; 3d. At the edge of that layer the in- 
terspaces become larger ; 4th, Finally, in the medullary sub- 
stance the interspaces become still larger and vertically 
elongated. 

Arfenes of iKe coney., 

""■ grev F.utstance uri -n 

_, A . _ ^ ^_^.,Medullaty 

"Arleriea 




Arteries of the commissural 
fissure of GraUoleL 

Fig. II. — Arterial distribution in the cerebral cortex. 

From the preceding facts it follows that, as concerns the 
arterial distribution, the gray and subjacent white cortex are 
a unit, since the vessels which they receive are derived in 
common from the arteries which traverse the pia mater. 
Should these last be obliterated at a given point, the gray and 
white substance would suffer simultaneously in the correspond- 
ing parts, and would be subject to that kind of mortification 
called isckcBuiic cerebral softening. The reciprocal relations 
of the parts permit a scheme of superficial softenings. 



ARTERIAL CIRCULATION IN THE I3RAIN. 49 

Recall the general distribution of the nutrient vessels. 
They are directed parallel to each other like so many lines 
towards the central parts. The white and the gray regions 
of the cortex can then, as vascular departments, be divided 
into a number of wedges, the bases of which are directed 
towards the encephalon, and the apices towards the central 
parts. This is, indeed, the form assumed by the greater 
number of those softenings called superficial. That at once 
calls to mind the appearance of infarctus of the spleen and 
kidney. If the softening is an old one — that is, of several 
weeks' standing — the gray substance appears depressed in 
consequence of the destruction of its elements and the con- 
comitant turning up of the subjacent white substance. 

The superficial portions of the softening produce a yellow 
spot. The yellow color belongs exclusively to the gray sub- 
stance, the subjacent softened white substance being only 
blanched, or sometimes lightly tinted with yellow. 

A. In this case we have supposed the obliteration of a 
branch of the second or third order. The obliteration of the 
trunk of the Sylvian artery itself might produce necrosis of 
all the gray cortex and of the subjacent white cortex also. 

The central parts would be entirely spared if the oblitera- 
tion occurred above the origin of the arteries of the corpora 
striata. 

B. It need not be supposed that all obliterations of this 
kind would necessarily and surely produce such disastrous 
effects. There are rare cases where, in fact, such obliteration 
of a branch of the Sylvian artery, or even the artery itself 
(I here take the Sylvian artery as example, it would be the 
same for the anterior or posterior cerebral arteries) — there 
are cases, I say, in which the obliteration in question has no 
appreciable, or, at least, but passing results. 

If this be so, it follows that the three main vascular terri- 
tories into which the brain is divided, and the departments 
into which they in turn are separated, are not strictly isolated, 
individual territories. They may communicate, and indeed 
do communicate in the ordinary manner. But are these 
communications easy and constant, or, on the contrary, are 
4 



50 DISEASES OF THE BRAIN. 

they accidental, indirect, and often impracticable ? In the 
solution of this question authors are at variance. 

Heubner holds that the communications in question are 
very easy, that they are made by the mediation of vessels not 
less than a millimetre in diameter. He rests that assertion 
upon the results of injections, where he has invariably observed 
that the material injected into any one of the departments by 
the principal trunk, or by the branches, always rapidly pene- 
trates the other territories. 

He also cites pathological cases which indicate that obliter- 
ation of one of the vessels of the cortical system or of its 
branches has, during life, given no evident symptom ; cases 
in which death having followed, the cerebral pulp in the parts 
corresponding to the obliteration has at autopsy presented no 
trace of softening. 

In the first place, as to the pathological facts of Heubner, 
we must recognize that they are real ; of this there is no 
doubt. At the same time, to judge from the very numerous 
observations which I have collected, they are certainly rare. 

On the other hand, it is certain that in anatomy things are 
far from being always as seen by Heubner. The observations 
of Duret in that field have been numerous, and are nearly 
always in accord. 

Here is briefly what we learn from them : 

Let ligatures be placed upon each of the three principal 
arteries at the base of the encephalon on both sides, immedi- 
ately above their origin in the circle of Willis. Then inject 
the Sylvian artery. This will first fill the Sylvian territory, 
and in the majority of cases it will pass beyond its limits. 
The injected material invades the neighboring parts slowly, 
little by little. This invasion is made from the periphery 
inwards towards the centre of the invaded territory. It is 
effected through the mediation of vessels of small calibre be- 
longing to the system of ramifications having diameters of but 
a quarter or a fifth of a millimetre, contrary to the opinion 
of Heubner, who holds that these anterial vessels have a diam- 
eter of one millimetre. 

The number of anastomoses from territory to territory 



ARTERIAL CIRCULATION IN THE BRAIN. 5 1 

are also quite variable. There are cases where one of the 
three grand territories can be injected isolatedly, the anasto- 
moses not being sufficient to permit the injection to enter the 
adjacent territories. The communication which may occur 
at the periphery of a vascular territory explains why the 
obliteration of a main trunk often results in the softening of 
only the central parts of the territory, the peripheral portion 
remaining untouched. 

Such are the conclusions of Duret, and to my mind they 
are more in conformity with pathological facts than those of 
Heubner. I should add that Cohnheim, who has also ex- 
perimented in partial injections of the encephalic arteries, 
agrees with Duret. He says if the arteries of the encephalon 
are wot final or terminal arteries (we will explain what Cohn- 
heim means by that term), they very nearly approach that type. 

Under the name of terminal ox final arteries (Endarterien) 
Cohnheim^ ingeniously catalogues those arteries or arteri- 
oles which, between their origin and the capillaries, neither 
furnish nor receive any anastomosing branch. An example 
of terminal arteries convenient for study is afforded by the 
tongue of the frog, upon which it is easy, through the micro- 
scope, to observe {de visit) all the effects of an obliteration. 
You see upon these schematic designs the various conse- 
quences of the obliteration of a terminal artery. The results 
are, as it were, certain. If, on the other hand, we deal with 
an anastomosing artery, generally the circulation is easily re- 
established below the point of lesion, by means of anastomo- 
ses. But these anastomoses may in their turn be obliterated, 
and it so may follow that an artery which in its normal state 
is not at all a terminal artery, may become so by accident. 

The encephalic circulation furnishes a great many examples 
of terminal arteries. Thus, without including the ramifica- 
tions which exist in the pia mater, we can instance the nutri- 
ent arteries. We see, too, that the arteries of the central 
ganglia are entirely and rigorously constructed on that model. 
The same type is found in all other circulatory systems where 

' UntersuchuBgen ueber die embclischen Processe. Berlin, 1872. 



52 DISEASES OF THE BRAIN. 

pathological or experimental lesions by vascular obliterations 
usually result in what is termed infarctus. Such are the 
spleen, the kidney, the lung, and the retina. None of the 
viscera — and this observation belongs to Cohnheim — where 
infarctus is not the rule, have the teruiinal mode of arterial 
distribution. 

But we will return to the relative individualities of the 
vascular territories of the brain. Those individualities do 
not belong exclusively to the large territories ; they are 
found also in the secondary departments, which correspond 
to the ramifications of arteries of the second and third order. 
Between these regions of the secondary order, the same as 
with the larger ones, communications are possible, but gene- 
rally are very difficult. It follows that obliteration of one of 
these secondary branches might have, and often does have, 
the effect of inducing limited mortification in the cortex. 
This is an important point in the study of cerebral localiza- 
tion. It might be that a lesion thus limited would exactly 
correspond to one of the convolutions, or to a group of convo- 
lutions, endowed with specific properties, manifesting them- 
selves during life through special phenomena. 

You can readily comprehend that strict localization of 
lesions of the cortex, produced by obliterations of arterial 
branches of the second or third order, would be an especially 
interesting study, when occurring in the Sylvian region. It 
is in that large field that experimentation tends to place the 
famous motor centres ; it is there also that clinical experience, 
aided by pathological anatomy, has located the faculty of 
articulate language. 

So it -is important that we should be well acquainted with 
the principal branches rising from the Sylvian artery, and 
closely examine their distribution in the fundamental convo- 
lutions of that region. 

The Sylvian artery divides into, or at least gives rise to, 
four principal branches. The distribution of these branches 
has been carefully studied by Duret and by Heubner. (See 
Figs. 9 and 12.) 

The first Duret calls frontal-external and inferior. That 



ARTERIAL CIRCULATION IN THE BRAIN. 



53 



is really the artery of the third frontal convolution (convolu- 
tion of Broca). I have myself several times seen an oblitera- 
tion of this arterial trunk produce a softening confined to the 



. C^t^^^}.^ 




•^eid. o£ "^ lobe. 

Fig. 12. — Vascular territories of the superior cerebral surface. (Duret.) The 
dotted lines indicate the territories of the anterior, middle and posterior arteries. 

territory of the third convolution (in its posterior part). I 
here add a conclusively corroborative fact. The case was 
a woman named Farn. . . . observed at Salpetriere. She was 
attacked with aphasia. There had existed no trace of paral- 
ysis either of motion or sensation. Aphasia was in this case 



54 



DISEASES OF THE BRAIN. 



the only symptom, and atrophy of the third convolution was 
also the only corresponding lesion revealed by autopsy. 
(Figs. 13 and 14.) This is incontestably a fine example of cere- 
bral localization.^ 

The second brancJi of the Sylvian is the anterior parietal 
artery of Duret. I prefer to term it the artery of the ascend- 
ing frontal convolution (Fig. 9 and Fig. 12). 




Fig. 13. — Human brain, anterior lobe, left side. {Life size.) 

The third is the posterior parietal artery, which I think 
would be better named artery of the ascending parietal con- 
volution (Fig. 9 and Fig. 12). 

The fourth branch goes to the gyrus angularis and the first 
sphenoidal convolution (Fig, 9 and Fig. 12). 

• We published the complete observations of that case in Nos. 20 and 21 of the 
Progres Mddical, 1874. 



ARTERIAL CIRCULATION IN THE BRAIN. 



55 



The two convolutions to which the second and third 
branches of the Sylvian artery are distributed furnish, accord- 
ing to the experiments of Ferrier upon the monkey, the mo- 
tor centres of the limbs. You see that from the arterial dis- 
tribution these two convolutions may suffer lesions independ- 
ently of each other. 

I do not know if the complete destruction of these two 




Fig. 14. — Human brain, anterior lobe, right side. {Life size.) 

central convolutions has ever been seen, but here is a case 
where entire destruction occurred of the ascending parietal 
convolution, which in the monkey is, according to Ferrier, 
the motor centre of the upper limbs, and partially so of the 
lower ones. 

In this case the convolution in question v/as replaced by a 
depressed yellow spot. The frontal ascending convolution 



56 



DISEASES OF THE BRAIN. 



was not greatly altered, though it was manifestly atrophied. 
Now, though the thalami optici and the corpora striata were 
in that case uninjured — their integrity was very explicitly 
mentioned — there existed a complete and permanent hemi- 
plegia in the upper and lower limbs of the opposite side 
(Fig- 15). 




Fig. 15.- 



-Human brain, left side ; destruction of the ascending parietal convolution 
and a great part of the frontal ascending convolution. 



This is a result which contrasts singularly with those 
accompanying two other observations relative to extended 
lesions occupying other portions of the gray cortex of the 
brain. In one case of limited destruction of the quadrilateral 
lobule (yellow spot) there was no corresponding paralysis. 
In another case, there was also a yellow spot which included 
a large extent of the inferior face of the sphenoidal lobe, 
which you know is arterialized by the posterior cerebral 
artery. Here, also, in life there existed not a trace of 
hemiplegia. 

I think these examples, which I could easily multiply, will 
sufifice to convince you that some day not far in the future, it 
will be possible to surely establish in the human subject the 
doctrine of localization, at all events as concerns the super- 
ficial parts of the brain. 

After the description which I have given respecting the 
Sylvian artery, I think I may be brief in that concerning the 



ARTERIAL CIRCULATION IN THE BRAIN. 



57 



subdivision into secondary department of the main cortical 
vascular territories of the anterior and posterior cerebral 

arteries. 

.off^alando 




Fig. i6. — Vascular territories of the internal or median face of the human brain, 
indicated by the dotted lines. 

III. The anterior cerebral artery is much less frequently 
the seat of serious alterations than the Sylvian. That fact is 
doubtless in part owing to the angle at which the Sylvian 
leaves the internal carotid artery (Figs. 12, 16, and 17). 

This artery gives three principal branches : the first nour- 
ishes the two inferior frontal convolutions ; the second, much 
more important, is distributed (less commonly than the 
Sylvian, but much oftener than the anterior cerebral) to the 
gyrus fornicatus (Fig. 16), to the corpus callosum, to the 
first frontal convolution (internal and external faces), to the 
paracentral lobule and upon the convex face of the frontal 
lobe, to the first and second frontal convolutions (Fig. 17), 
and finally to the superior extremity of the ascending frontal 
convolution. The tliird branch of the anterior cerebral artery 
is sent to the quadrilateral lobule, which may be subject to 
lesions on its own account, as I have just now given you an 
example. 



58 



DISEASES OF THE BRAIN. 



IV. The posterior cerebral artery (Figs. 12, 16, and 17) 
often suffers alterations by embolismus and thrombus. 

Ischa;mic softenings of the posterior lobes are much more 
common than with the anterior lobes. 

The territory of this artery is divided into three secondary 







Fig. 17. — Vascular territories of the inferior face of the human brain, indicated by 
the dotted lines. 

departments, corresponding to three arteries of the second 
order. The first of these goes to the gyrus angularis ; the 
second to the inferior part of the sphenoidal lobe, embracing 
the inferior sphenoidal convolution and the fusiform lobule ; 
the third goes to the lingual lobule, to the cuneus, and the 
occipital lobe proper. 



SEVENTH LECTURE. 

CIRCULATION IN THE CENTRAL MASSES (GRAY GANGLIA 
AND THE INTERNAL CAPSULE). 

Summary :— Arterial Circnlation in tlie Gray Central Ganglia; Intra- 
Enteplialic Hemorrliagc.— Anatomico-Patliological Differences be- 
tween tlie Peripheral and Central Parts of the Brain— Relative In- 
freqnency of Cerebral Hemorrhage in the Peripheral Regions; its 
Frequency in the Central Parts.— Origin of the Arteries of the Cen- 
tral System.— Terminal Arteries; their Characters.— Independence 
of the Cortical and Central Arterial Systems.— Analogies between 
the Arteries of the Protuberance, the Bulb, and the Central Ganglia. 
—Their Mode of Origin Explains the Predominance in those Parts of 
Arterial Ruptures.— Branches Composing that System rise from the 
Anterior and Posterior Cerebral Arteries and the Sylvian Artery.— 
Arrangement of the Gray Ganglia ; their Form and Relations.— Con- 
siderations upon the Internal Capsule ; its Constituent Parts (Direct 
Peduncular Fasciculi, Indirect Peduncular Fasciculi, Diverging 
Fasciculi). 

Gentlemen : 

In the preceding lecture I concluded the anatomico-medi- 
cal description of the cortical arterial system of the brain. 
I now purpose to call your attention to the arterial circu- 
lation in the gray central ganglia. Under this term are 
included the thalami optici, the corpora striata, and their so- 
called appendages. This is a study which should receive our 
closest care, for the phenomena which result from vascular 
lesions in these ganglia are clinically of no less importance 
than those which come from alterations in the arterial system 
of the superficial or cortical parts of the hemispheres. We 
will find in these central parts of the brain ischaemic altera- 
tions such as belong to its superficial layers ; but, besides 
these, we will there find, and upon a larger scale, lesions which 
are rare upon the periphery, I refer to common intra-ence- 



60 DISEASES OF THE BRAIN. 

phalic hemorrhage, one of the most constant anatomical 
causes of those symptoms signified by the term apoplexy. 

In this connection there exists a difference sufficiently in- 
teresting to be noticed between the peripheral and central 
parts of the brain. In the periphery, intra-encephalic hem- 
orrhage is relatively rare, whereas in the centre it is common. 
This is a fact of which the statistics of Andral and Durand- 
Fardel are eloquent witnesses, and they are confirmed by 
recent statistics. Thus, of 119 cases collected by Andral 
and Durand-Fardel, the thalami optici and corpora striata 
have been found the original seat of hemorrhage in 102 
cases ; in only 17 cases has the hemorrhagic origin been either 
in the anterior or posterior lobe or at the periphery of the 
brain. On the other hand, ischemic softenings of the brain 
predominate, as Durand-Fardel truly says, in the periphery. 
The facts which I have gathered at Salpetriere in every point 
confirm these statements. 

We will presently indicate some of the conditions necessary 
to explain this remarkable contrast ; just now it is sufficient 
to convince you that our review of the corticitlar arterial 
system was a necessary introduction to the chapter upon 
ischaemic softenings of the brain ; the studies which will oc- 
cupy us to-day furnish the obligatory preface of the equally 
interesting history of intra-encephalic hemorrhage. 

I. You remember how the arterioles of the central system 
are derived from the three great arterial trunks of the brain, 
near their origin in the circle of Willis. The arteries which 
form the central system are generally vessels of some size. 
For the corpora striata they are, according to Duret, arteri- 
oles measuring in diameter from a half to one and a half 
millimetres. 

Their mode of origin calls to mind the shoots rising from 
the base of forest trees. I borrow the comparison from 
Heubner, which, beyond its picturesque character, is quite 
true ; only it must not be carried too far, for the arteries of 
the central system, at their point of departure, take a direc- 
tion perpendicular to the principal trunk. 



CIRCULATION IN THE CENTRAL MASSES. 6l 

This perpendicular direction brings to mind that which we 
have noticed respecting the nutrient arteries of the cortex. 
But it is well not to forget that there is a difference between 
the nutrient cortical vessels and the arteries of the gray cen- 
tral ganglia; the first, indeed, are but capillaries — at least as 
defined by Robin — and the second, on the contrary, are ves- 
sels of larger size. 

Another character belonging to the arteries of the central 
ganglia is that (as the term is used by Cohnheim) they are 
terminal arteries par excellence. If the independency of the 
vascular territories of the cortex is, as we have seen, open 
to discussion, it is not the same respecting the central arteries. 
Authors fully agree that they are entirely independent of 
each other. 

Thus Heubner says that by the aid of a Pravaz syringe 
(its point blunted) one can inject each of the small arteries 
that lead to the various parts of the corpora striata and 
thalami optici. With all possible precautions, however, one 
can never inject the entire body of the thalamus opticus or 
corpus striatum. Only small departments of each can be 
injected, and if the injection is made too forcibly, ruptures 
are produced ; but notwithstanding that, the vascular territo- 
ries keep to their assigned limits. 

The multiplied experiences of Duret are to the same effect. 
It should be added that tinder no circumstances can an injec- 
tion be passed by way of the central arteries into the domain of 
the cortical arteries, and the reverse is equally true — the cen- 
tral system cannot be injected through the cortical. 

It is perhaps not without interest to notice the analogies in 
the manner in which the nutrient arteries originate in the basi- 
lar parts of the encephalon, in the protuberance, and even in 
the bulb. 

In \\iQ protuberance the resemblance is striking; the me- 
dian arteries leave the voluminous basilar artery at right 
angles and penetrate to the posterior part of the protuberance 
parallel to each other and without anastomosing, reproduc- 
ing somewhat the type of terminal arteries. 

In the biUb the same method exists, but somewhat differ- 



62 DISEASES OF THE BRAIN. 

ing through a special modification. The median arteries of 
the bulb do not rise immediately from the great trunks of 
the vertebral arteries ; they have their origin in the spinal 
arteries. 

This mode of origin and distribution of the arteries of the 
protuberance and the central ganglia, possibly explains one 
of the reasons (a mechanical one) of the predominance in 
those parts of arterial rupture. 

Remember that at the surface of the brain, where, as I 
have said, hemorrhages are comparatively rare, the arteries 
are not admitted to the pulp except after a long journey 
through the pia mater, and after being transformed into very 
slender vessels, in fact capillaries — recall, I say, these peculiari- 
ties, and you will much more easily comprehend the differences 
which I have pointed out to you concerning the central 
arteries. 

1st. The distance from the heart to the large ganglia of the 
base is very short. The arteries supplying these ganglia 
come directly from the arteries forming the circle of Willis, 
that is, from arteries of the third order from the heart. This 
is evidently favorable to arterial ruptures. To be sure, this 
is obviated to a certain degree by the right angle at the ori- 
gin of the vessels, and also by a considerable reduction of 
calibre. 

2d. Compared with the cortical arteries, the central are 
voluminous ; I allude especially to the arteries of the corpora 
striata, which have a diameter of one-half to one and a half 
millimetres. 

3d. I would add that the absence of anastomosis seems an 
unfortunate condition, for in case of increased pressure in a 
vessel, the clearing of the way is impossible on account of 
the absence of well-established collaterals. 

The three great arterial trunks of the brain all take part in 
the vascularization of the central regions, but that participa- 
tion is very unequal. The anterior cerebral, for example, 
sends only a few vessels to the head of the corpus striatum, 
and even these inconstantly. The posterior cerebral artery 
has a domain much more vast and important. It supplies 



CIRCULATION IN THE CENTRAL MASSES. 63 

the thalami optici, and to a great extent the superior portion 
of the crura cerebri and the tubercula quadrigemina. But 
here, as in the cortical system, the Sylvian arteries incontesta- 
bly play the preponderating role. These arteries furnish all 
the branches which go to the caudated ganglion (with the 
exception of a little field of variable branches from the ante- 
rior cerebral) and to the various segments of the lenticular 
ganglion. 

We will consequently take the branches of the Sylvian ar- 
tery for the type of our description. After that, it will be 
easy to complete the description of the central nutrient sys- 
tem with the addition of a few words concerning some 
branches, derived, as may chance, from either the anterior 
or posterior cerebral arteries. 

II. But before entering into the detailed description of 
these vessels it is very necessary to examine more closely 
than we have hitherto done the parts to which they are dis- 
tributed. In the preceding description we have done little 
else than to name the parts, and in a summary manner to 
indicate their general configuration. That rapid notice is 
insufficient. We must enter into such examinations as are 
necessary to the acquisition of a thorough anatomical knowl- 
edge. 

I need not repeat that it relates to those parts so interesting 
as concerns the theory of cerebral localizations, namely, the 
tJialanii optici, the caudated ganglion, the lenticular ganglion, 
and the internal capsule. Such are the various constituents 
which united form that which is called the central system, in 
distinction from the cortical system. 

Bring to mind how the crura cerebri, rounded at the point 
where they border the thalami optici, flatten after having 
passed it, internally and externally spreading forward and 
backward like a fan. Upon that fan — allow me to continue 
the simile — the ganglia of the gray substance are arranged as 
follows : the thalami optici within and posteriorly ; within, 
but before and above, the caudated ganglion ; outside of the 
fan, and below the thalami optici and caudated ganglion, is 



64 DISEASES OF THE BRAIN. 

situated the lenticular ganglion, which extends nearly as far 
forward as the head of the corpus striatum, and backward 
nearly as far as the posterior extremity of the thalami optici. 

I only wish to indicate, en passant , the forms and principal 
relations of the gray ganglia which I have enumerated. 

1st. The thalamus opticus has a flattened, ovoid appearance. 
The superior face looks upon the lateral ventricle, and the in- 
ferior, which is also the internal, upon the middle ventricle. 
On dissection it is with difficulty separated, on account of its 
numerous and close connections with contiguous parts. 

2d. The candated ganglion has the form of a comma — or 
of a pyramid — the large end of which is directed forward 
and inward, the small end upward and outward. Its su- 
perior face protrudes into the ventricle ; the so-called internal 
face is mostly in contact with the superior portion of the in- 
ternal capsule. This ganglion is very easily detached in 
dissections, but in order to isolate it, the numerous fasciculi 
which it receives from the internal capsule must be broken. 

3d. The lenticular ganglion, although all its surface is cov- 
ered, can easily and without much art be isolated from the 
neighboring parts. Its general form is ovoid, with an an- 
terior and a posterior extremity. There can be distinguished 
in it two parts : {a) The anterior third, more obtuse, and com- 
posed of a uniform mass of gray substance, is, at its very an- 
terior extremity, confounded with the intraventricular nu- 
cleus of the corpus striatum, {b) The second portion, the 
posterior two-thirds of the lenticular ganglion, is flattened 
from above downward in such wise as to offer an angle 
turned inward towards the internal capsule. The internal 
and superior face is intimately united to the internal capsule, 
and the inferior face is parallel with the base of the brain. 
The external face is in rapport with the external capsule, and 
its intermediate with the front wall of the island of Rail. 
The island lies close to it in its entire extent. An interesting 
preparation consists in carefully removing successively the 
gray substance of the convolutions of the island, the anterior 
wall, and the external capsule, which lays bare the external 
face of the lenticular cranslion. 



CIRCULATION IN THE CENTRAL MASSES. 65 

In hardened specimens the separation between the external 
face of the lenticular ganglion and the external capsule is 
effected without art and with the utmost ease. This is be- 
cause there are no medullary fasciculi — and you see that 
there are no vessels — which bind the external capsule to the 
third segment of the lenticular ganglion. 

From the connections which we have outlined it might be 
said that the three ganglia or gray central masses — thalamus 
opticus, caudated ganglion, and lenticular ganglion — arc in 
some sense, as Foville has said, appendices to the internal 
capsule, like cotyledonal prolongations of the crura cere- 
bri. 

On the side of the ventricles the thalami optici and the 
caudated ganglia are isolated ; the lenticular ganglion is also 
isolated, virtually, at least, on the side of the island. These 
gray ganglia, then, form a distinct system from the other parts 
of the brain, as well by their connections as by their mode 
of vascularization. 

Vertical sections will enable you to easily understand the 
relations of the central parts. I will not at this point dwell 
upon the structural details of the different ganglia, but will 
return to them as occasion requires. Some examination and 
idea of the construction of the internal capsule, however, is 
indispensable. 

The internal capsule, in part at least, is the prolongation, 
not of the entire crus cerebri, but of \}LiQ. foot or crust a, the 
inferior part only. The tegmentum or superior part, which 
is separated from the foot by the locus niger, enters into rela- 
tions especially with the tubercula quadrigemina and the 
thalami optici ; it takes no direct part in the formation of the 
internal capsule. 

An old opinion held the internal capsule as a complete and 
immediate emanation from the foot of the diverging fibres. 
This is an error which Luys and KoUiker have corrected. 
These authors have, in fact, demonstrated that the fibres com- 
ing from the peduncle stop by the way to enter various 
ganglia. I think, however, they have gone too far, in holding 
that the internal capsule is entirely formed, ist, of diverging 
5 



66 DISEASES OF THE BRAIN. 

fibres which terminate in the ganglia ; 2d, of fibres which 
leave the ganglia and become diverging fibres. 

From very delicate anatomical observations, Meynert, 
Henle, and Broadbent have expressed the opinion that there 
exists a third order of fibres which communicates directly 
from the foot of the peduncle to the gray cortex. 

The verification of the existence of these last fasciculi de- 
pends, as you will see, upon certain pathological proofs. I 
will cite, among others, some cases of descending degenera- 
tions observed by Vulpian and myself. In the cases referred 
to, destruction and yellow spots had largely invaded the 
median convolutions, without concomitant alterations of the 
corpora striata, and had produced progressive degeneration, 
which could be followed across the isthmus and to the lower 
region of the spinal cord. We are indebted to Gudden for a 
series of experiments which I will later have occasion to 
notice, and the results of which have the same bearing. 

Henle ' goes too far, perhaps, when he writes in his de- 
scription of the nervous system that the internal capsule is 
composed entirely of the fibres from the foot of the peduncle. 
Certainly — and we will have occasion to return to this sub- 
ject — both pathological and experimental facts in favor of the 
existence of these fibres are numerous and important, and 
the facts permit a belief (we will further on see the demon- 
stration), that among the direct fibres some (the anterior) are 
centrifugal and connected with movements of the limbs, 
while others (the posterior) are centripetal and connected 
with the transmission of sensorial impressions (Fig. i8). 

To sum up, the internal capsule, according to modern re- 
searches,^ is composed as follows : 

1st. By the direct pediinciilar fasciculi, which traverse the 
capsule without entering the ganglia. 

2d. By the indirect peduncular fasciculi. Of these some 
are sent to the corpora striata, which they approach by the 
inferior face ; others go to the lenticular ganglia, which they 

' Henle. — Nervenlehre, p. 261. 

- Huguenin. — Allg. Patholog. der Krankli. des Nervensystenis ; Zurich, 1873, 
p. 94, Fig. 70; p. 85, Fig. 63 ; p. 119, Fig. 82 ; p. 127. 



CIRCULATION IN THE CENTRAL MASSES. 



^7 



penetrate by its first segment. Very numerous in this seg- 
ment, they become less and less in the second and third seg- 

Fibers of optic thalamus 
extending to the periphery 

Caudated nucleus i Titers of caudaled nucleus 
extending toTthe periphery 



J)irec<3 
fibers. 




Fig. i8. — Scheme illustrative of the different orders of peduncular fibres. — 
Huguenin. 

ments, and to that unequal distribution is due the difference 
in color of the three segments of the lenticular ganglion. 



68 



DISEASES OF THE BRAIN. 



There is no question as to whether the fibres from the foot 
of tiie peduncle go to the thalami optici ; the thalami optici 
receive no other fascicuh from the cerebral peduncles except 
those from the tegmentum. 

To the fasciculi which go from the foot of the peduncle to 



Piters from the 2 int.Segnents of lent, nuclei i-s, 

Caudated nucleus; ; 

ExieraalportiQU of optic thalamus^ 
Lit. portion of optic th^^^ 



Titers from Qia 
lapetum. 




^— ,Z^^te^ \ /int . Capsule,' 
-'Optic nerve '■ ' • ' 



"•^Anterior coituaLssure 
'\// 'Lenticular nucleus. 



<L Optic e:anf?;lion . 'JJasilar portion 
•^ o '^ Of caudated nucleus. 

VThree layers of unnamed sutst^nce. 

Fig. 19. — Section of lenticular ganglion and its surroundings. — {ifi-yncrt.) 

the gray central ganglia are added, in the superior part of 
the internal capsule, fasciculi which originate in the gray 
ganglia, and go towards forming the diverging fibres that 
run to the gray layer of the cortex. These fasciculi bear the 
name of radiating fasciculi i^St abkran zbluidcl) . There can be 
distinguished, 1st, the diverging fasciculi of the corpora stri- 
ata ; 2d, the radiating fasciculi of the thalami optici ; 3d, the 
radiating fasciculi issuing from the lenticular ganglion, which 
come principally from the superior border of the second and 
third segments. 



CIRCULATION IN THE CENTRAL MASSES. 69 

It follows from this exhibit that four orders of fasciculi cntci" 
into the composition of the diverging fibres, and so attach the 
internal capsule to the cortex of the convolution. 

They are : ist, the radiating fasciculi of the thalami optici ; 
2d, those of the corpora striata; 3d, those of the lenticular 
ganglion — these various fasciculi attach the gray central gan- 
glia to the cortex ; 4th, the direct fasciculi which go from the 
foot of the peduncle to the gray cortex without stopping in 
the gray central ganglia. 

In the internal capsule itself, and also in the foot of the 
diverging fibres, one can recognize these various modes of 
origin by submitting thin slices, properly hardened, to a low 
power of the microscope ; to be sure, the research is not ex- 
empt from difficulty. A little above that point, however, all 
the fasciculi intermix in the most varied manner, either among 
themselves, or it may be with the commissural fibres, in such 
manner as to form an inextricable net-work, called the central 
white substance. We will soon render an exact account of 
the interest pertaining to this arrangement. 



EIGHTH AND NINTH LECTURES. 

CENTRAL ARTERIES.— ISOLATED LESIONS OF THE GRAY 

GANGLIA. 

Summary !— Origin of tlie Arterial Syslciii of tlie Central Ganglionic 
Masses. — I'ncqiial Participation of ilic Main Arteries of tlie Brain 
Constituting tliis System.— Description of tike Striated Arteries; In- 
ternal Striated Arteries; External Striated Arteries (Lenticnlo-Stri- 
atcd, Lientieulo-Optie). — Terminal Arteries. — Consequences of Obliter- 
ationsof Central Arteries Kmanating from tlie Sylvi.-»n Artery. — Soft- 
ening of tUe Optico-Striated Bodies Iiitra-Knceplialic Hemor- 
rhage— Regional Diagnosis.— Isolated Lesions of the Gray Ganglia 
-ivithotit Participation of the Internal Capsule. — Cerebral Hemi- 
plegia, Central and Cortical. — Ijesions of the Internal Capsule.— 
Variations of Symptoms according to tlie Spot in the Internal Cap- 
sule Occupied hy the licsions. — IVew Anatomical Considerations i Pe- 
duncular Fibres going Directly to the Cortical Substance of the 
Occipital liobe ; their Role Relative to Sensibility. — Proofs Fur- 
nislted, 1st, by Ijesions of the Posterior I<enticulo-Optic Regions 
of the Internal Capsule (Hcmi. Anaesthesia Cerebral); 3d, by Ex- 
perimentation. 

Gentlemen : 

I. You remember that the three great arteries of the brain 
take an unequal part in forming the arterial system of the 
ce7itral ganglionie masses. 

A. — [a.) Thus, the Sylvian artery very greatly predomi- 
nates. It furnishes : ist, in great part, the caiidated ganglioji ; 
2d, the entire lenticular ganglion ; 3d, a portion of the thala- 
mus opticus ; 4th, the whole extent of the internal capsule. 

{b.) The anterior cerebral artery has, on the contrary, very 
modest attributes. It arterializes only the head of the cau- 
dated ganglion, and even in this its participation is not con- 
stant. 

(<:.) As for the posterior cerebral artery, its role is more 



CENTRAL ARTERIES. 



important and tolerably characteristic. That artery, which is 
extensively distributed (as it sends branches to the choroid 
plexuses, to the ventricular walls, etc.), furnishes the following 
regions of the central masses : ist, the external and posterior 
part of the thalami optici ; 2d, the tubercula quadrigemina ; 
3d, the superior portions of the crura cerebri. 

Section of lat .ventricle. 

^Trigone pillar 

^v \r{s.[ed. nuclfiU3» 




Int. arteries >' 

of cor pus sirialum. 



I ^t.t'erebiarty _^ ,^ 
Llnt.car'dt.ai;tery, (Lent;nucleus of corp.stnaiiirai 
[Sylvian aijtkiy. ; (Ext . capsule . 



ChiflsmaofopUc nerves). 1 
Grey substance of 3* ventriclj. iSection of Optic iand. 
Fig. 20. — Transverse section of the cerebral hemispheres, one centimetre posterior 
to the optic chiasma. Arteries of the corpora striata..— (Duret.) Vascular territories 
indicated by dotted lines. 

The plates (Figs. 20 and 21), on which the vascular ter- 
ritories are separated by dotted lines, will make the details 
clearer. 

The description of the striated arteries alone requires some 
explanation. With this you will possess, in brief, all that is 
necessary to a knowledge of the central arteries, whether they 
come from the anterior or the posterior cerebral arteries. 

Emanating from the superior border of the Sylvian artery, 
the striated arteries enter the apertures of the anterior per- 
forated space, where they soon disappear from sight. But a 
very simple preparation renders it possible to follow them in 
the first part of their intracerebral course. I solicit attention 
to the following description, because that, in order to under- 



72 



DISEASES OF THE BRAIN. 



stand some important facts, it is indispensable to know the 
theory of common cerebral hemorrhage. 

That exposition consists in destroying successively the 
gray cortex of the island of Reil, the subjacent white sub- 
stance, the anterior wall, and finally the internal capsule. 




Lenticular 

Horn cf Anmion 



Sphenoidal Horn 
oflat.Vealricla 



Post . cerebral Arteries 



Fig. 21. — Vertico-transverse section of the human brain, posterior to the tuber- 
cula mammillaria and anterior to the peduncles. Vascular territories indicated by 
dotted lines. 

Thus the entire external surface of the lenticular ganglion is 
laid bare. If the preparation has been somewhat carefully 
made, upon a well-injected brain — and the preparation is 
easily made, because, in its anterior part at least, the lenticu- 
lar ganglion is as it were naturally detached from the internal 
capsule — one can follow the first part of the distribution of 



CENTRAL ARTERIES. 73 

the principal striated arteries. By this artifice it is seen that 
they spread hke a fan at the surface of the gray gangha. But 
at a short distance from their origin they bury themselves 'in 
the substance of the third segment, where they disappear. 

Now, it is upon the transverse sections that one must fol- 
low the ulterior distribution of the striated arteries. 

A first section, made behind the chiasma (Fig. 20), shows 
only the caudated and lenticular ganglia, the thalami optici 
being more posterior. Upon that section are found the 
deepest tracts of the arteries which we have just had under 
observation. Besides these, other and smaller arterioles may 
be discovered on the external surface of the lenticular ganglia, 
and which may be termed iiiternal ; after detaching them- 
selves from the Sylvian trunk, they rise nearly perpendicularly 
into the first two segments of the lenticular ganglion and the 
adjoining parts of the internal capsule. 

Of still greater interest are the exterjial striated arteries, 
those which, in the first part of their course, run over the 
external face of the lenticular ganglia. They should be 
divided into two groups : the first group is anterior, and the 
arteries of which it is composed are the lentictilo-striated 
arteries ; the second group is posterior, and the arteries which 
constitute it are the lenticulo-optic arteries. 

One of the arteries in the anterior group is especially 
important on account of its size and its predominant role 
in intra-encephalic hemorrhage ; it could be appropriately 
called the artery of cerebral hemorrliage. After having en- 
tered the third segment it traverses the superior portion of the 
internal capsule, then enters the body of the caudated ganglion. 
It then continues from behind forward to the most anterior 
part of that ganglion. 

The distribution of this striated artery, as well as that of 
the lenticulo-striated arteries, should be studied from sections 
made anterior to the one which has thus far served us. 

The lejiticulo -optic arteries are after the same model, only 
after having traversed the most posterior part of the internal 
capsule, they encounter the external and anterior part of the 
thalamus opticus, over which they spread. 



74 DISEASES OF THE BRAIN. 

I would remind you that we arc dealing with terminal 
arteries, and that if the injections are too strongly pressed 
they will produce little ruptures upon different points of the 
vascular tract, thus imitating in locality, as well as in form, 
the centres of hemorrhage which are produced pathologically. 

About the branches of the ajiterior cerebral artery, we 
have nothing especial to say, except that they do not con- 
stantly exist, and that they give place to very circumscribed 
hemorrhages, though really grave, inasmuch as they often 
open into the ventricles. 

As for \he posterior cerebral artery, I repeat that it merits 
by itself more minute attention. I only wish to notice here 
the arteries which it sends to the thalami optici. 

These arteries are of two orders : 1st, t\\Q posterior internal 
optic artery, arising from the posterior cerebral near its origin 
at the basilar trunk, and which furnishes the internal face of 
the thalamus opticus, and is capable in its ulterior tracts of 
occasioning hemorrhages, of small extent to be sure, but 
serious, as being often followed by ventricular inundation ; 
2d, \\\Q posterior external optic artery, which comes from the 
posterior cerebral after it has passed around the crus cerebri, 
and in which it ascends obliquely before entering the posterior 
part of the thalamus opticus. The rupture of this vessel 
produces hemorrhage which often breaks into the body of the 
crura cerebri. This artery deserves your close attention, for, 
as you will see later, lesions within its territory produce a 
train of symptoms altogether peculiar to themselves. 

II. In journeying along we have gathered facts in the 
highest degree interesting for the theory of cerebral patho- 
logical localizations, and we will now examine these facts more 
closely, commencing with those which concern the central 
ganglionic masses. 

A. {a.) The entire system of the central arteries emanating 
from the Sylvian, may be obliterated in consequence of a 
thrombus or an embolus of the principal arterial trunk. 
Then follows softening of nearly the entire mass of the gray 
ganglia, the district corresponding to the anterior cerebral 



CENTRAL ARTERIES, 75 

?in6. the posterior Optic arteries alone being spared. Here is 
a very concise localization, generally of an extreme gravity, 
and which embraces, clinically speaking, all the pathology of. 
the ganglionic centres. The symptoms which belong to a 
softening of the entire optico-striatcd bodies (the entire cen- 
tral masses are sometimes so called) are none other than 
common cerebral hemiplegia accouipanied with cerebral henii- 
aiiasthesia. 

{b.) Analysis may be brought to bear on this complex 
whole. We must not believe, however, that we are at present 
able to recognize the special symptoms which belong to the 
destruction of the thalami optici, the caudated ganglia, or the 
lenticular ganglia, and still less to the various segments. 

(<r.) It is possible, however, by reason of the arterial distribu- 
tion which we have described, that the anatomical locality 
may betray itself by special symptoms, thus affording a re- 
gional diagnosis. This is realized when the softening affects 
all, or nearly all, of the territory of the lenticulo-striated arteries, 
or that of the lenticulo-optic arteries. The two different events 
differ in their symptoms ; the symptoms of hemianaesthesia are 
present when the field of the lenticulo-optic arteries is invaded, 
and absent when the lenticulo-striated arteries are the ones 
involved. 

B. That which has been said relative to ischaemic softening 
is also applicable to intra-encephalic hemorrhage. This, you 
know, is frequent, and especially in these regions ; the striated 
arteries are, indeed, very prone to a special form of arterial 
sclerosis which produces miliary aneurisms. One often ex- 
tracts from a recent hemorrhagic centre a striate or an optic 
artery, the prolongations of which have small aneurisms.^ 

Contrary to current opinion, sanguineous effusion gener- 
ally occurs (as Gendrin has long since recognized"), in such 
cases, not at first in the body of the corpus striatum it- 
self, but outside of it — to be more exact, in contact with the 
external surface of the lenticular ganglion, between that and 



' See plate V. oi Archives de physiohgie, iS6S. 

^ A. N. Gendrin, Traite philosophique de medecuie pratique.^ t. I., 1S3S. See 
page 443, Nos. 7S9, 796; p. 465, Nos. 80S, 809, 810; and page 47S, No. 830. 



76 



DISEASES OF THE BRAIN. 



the external capsule, which becomes detached. Thus are 
produced those flat centres which upon transverse sections 
appear Hke narrow hnear lacunae, nearly vertical, and parallel 
to the gray ganglion of the front wall (Fig. 22). When the 
sanguineous effusion is abundant the hemorrhagic centre 
extends, especially transversely, and on account of the greater 
resistance of the cranial walls and the wall of the island, the 
central masses, enucleated so to speak, are crowded back en 
bloe towards the ventricular cavity (Fig. 22). 

Lateral "Venlnde^ 




I -ragic center / 
de^ti \j) iiig ext . capsule, 

L enticulo - sliuata portion of int. capsule. 

Fig. 22. — Extra-lenticular hemorrhagic centre, posterior to the optic chiasma. 
{A'o he?niancest/iesia.) 

I have given very ordinary cases, but it may happen also 
that extravasation coming from the extremities of the termi- 
nal arteries will occur in the body even of either the corpus 
striatum or of the thalamus opticus. 

Be that as it may, the only clinical localization possible in 
these cases is, as in case of softening, those which corre- 
spond to the Icnticulo-striated or the lenticulo-optic domains. 

The symptoms of hemorrhage are at present more difficult 
of interpretation or of exact localizing than are those of 
softening. Uninformed, one would be liable to attribute 



CENTRAL ARTERIES. 'J'J 

certain symptoms to the destruction of a part which really 
was only the result of a neighboring accident. I allude to 
compression, which, during effusion, however slight it may be, 
never fails to somewhat affect the adjacent parts This is a 
point to which I will shortly return. 

III. The definitely acquired facts relative to regional diag- 
nosis concerning the various parts which enter into the com- 
position of the central ganglionic masses of the brain can be 
reduced to a very small number of propositions. 

1st. Regarding lesions confined to any one of the gray 
central ganglia, and zvJiere the internal capsule is not i?i- 
volved, we are not at present able, from clinical examination, 
to recognize any special characters. 

{a.) Thus it is impossible to distinguish, during life, a lesion 
limited to the lenticular ganglion from one confined to the 
caudated ganglion, and lesions of the thalamus opticus (though 
upon this last point there is reason perhaps for some reserve) 
generally confound themselves clinically with those produced 
in the two compartments of the corpus striatum. 

The symptoms which accompany lesions limited to the 
gray central ganglia are those of connnon cerebral Jieniiplegia. 
That form of cerebral hemiplegia may be called central^ to 
distinguish it from motor paralysis, which sometimes results 
from superficial lesions, and which in distinction I will call 
cortical cerebral hemiplegia. 

{b.) Paralysis, dependent upon lesions of the gray central 
ganglia, is generally of motion only ; disturbances of sensa- 
tion such as belong to cerebral Jieniiancesthesia are, however, 
sometimes added, under special circumstances to which we 
will shortly give attention. 

{c.) Hemiplegia, dependent upon alterations confined to the 
gray ganglia, is generally transitory, passing, lightly marked 
not indelible, and in any case is at first comparatively 
benign. It is understood that in formulating this proposi- 
tion I remove all complications capable of greatly modify- 
ing the picture ; such, for example, would be the eruption 
of a hemorrhage, however small, into a ventricular cavity. 



78 DISEASES OF THE BRAIN. 

Grave symptoms, such as early contractions, or epileptiform 
convtclsions, almost necessarily ensue in such cases, and more 
or less rapid death is generally the necessary consequence 
of such complication. 

The relative benignity of lesions limited to the gray ganglia 
arises in part, doubtless, from the fact that these ganglia are 
scarcely ever affected in their totality. Thus the caudated 
ganglion, for example (and the fact is explained b}^ the 
method in which the vessels going to it are distributed), is 
never destroyed in its entire extent, at least by itself, that is 
to say, without the participation of the internal capsule or 
other gray ganglia. On the other hand, the transitory char- 
acter of a paralysis resulting from partial lesion of the cen- 
tral ganglionic masses may indicate, as we will see, a sort of 
functional supplement established between the various parts 
of the caudated ganglion, or between the caudated ganglion 
and the various segments of the lenticular ganglion. 

2d. Then, again, lesions of the internal capsule, even when 
strictly limited to the white tract, in no degree including the 
substance of the gray ganglia — these lesions, I say, generally 
produce common cerebral hemiplegia of a very marked and 
more or less persisting form. Thus, even when very circum- 
scribed (principally when they are situated low down at the 
side of the peduncle), these lesions produce a motor paralysis 
almost necessarily accompanied by late eontractio>is ; a symp- 
tom of bad augury in these troubles, because as a rule it an- 
nounces that the paralysis will resist all therapeutical means. 

3d. It is proper to establish here an important distinction. 
Wc have already said that the symptoms differ remarkably 
according to the portion of the internal capsule affected by 
the lesion. 

If it occupies any part of the anterior tzvo-thirds of the 
capsule, the region where the white tract separates the ante- 
rior extremity of the lenticular ganglion from the head of the 
caudated ganglion, and which belong, as you know, to the 
field of the lenticulo-striated artery, t\\Q paralysis will be ex- 
clusively that of motion ; there will be no durable trouble of 
sensation. 



CENTRAL ARTERIES. 



79 



On the contrary, if the lesion having invaded the domain 
of the lenticulooptic arteries should extend to the posterior 
third of the capsule, in that region where it passes between 
the posterior extremity of the lenticular ganglion and the 
thalamus opticus, the presence of cerebral hemiansesthesia 
would be almost certain. Most frequently the lesion extends 



Posterior extremity, 
of caudatednudetis 



Carpus CaHosum.cmd 
pos1 .pillars- of the Arch. 

.Lateral Ventricla. 




IsTe \m 

c£ReiU'im 

Ext'l.Wall 



Horn of Ammon? 
and sphenoidal 1^ 
horn of lat.YentriclfS^ 



^ 'ventre. 1 ... 
portion including 
internal capsule). 



ernal Capsule. 
'"Lenticular Nucleus. 



Fig. 23. — Extra-lenticular hemorrhagic centre on a plane with the posterior por 
tion of the thalamus opticus. [Cerebral heiniancesthcsia.) 

to several parts, and paralysis of sensation will be accom- 
panied with a more or less marked motor hemiplegia. But it 
may happen that cerebral hemiansesthesia will occur alone, at 
least as a permanent phenomenon, in those cases, for example, 
where the most distant parts, the most posterior portion of 
the internal capsule would alone be definitely altered (Fig. 

23)- 

In the preceding expose I have purposely alluded only 
to truly destructive lesions of the internal capsule, to those 
which, either by lacerations or necrosis, produce an irrepa- 
rable loss of substance. It is necessary, however, to distin- 
guish those cases where the internal capsule is not directly 
involved, but affected by proximity to a neighboring phe- 
nomenon, that is, the consequence of a lesion limited to the 



8o 



DISEASES OF THE BRAIN. 



gray ganglia which surround the capsules. Thus the disten- 
tion of one of these ganglia, in case of interstitial hemor- 
rhage, might compress the nerve- fibres that compose the in- 
ternal capsule and so suspend their functions. But as the 
nerve-fibres in such cases are only compromised and not de- 
stroyed, the paralytic phenomena resulting from that com- 
pression (excepting cases of tumor) would always be tempo- 
rary. 

The combination which I have brought to your notice is 
frequently met in the clinic of intracerebral hemorrhage ; it 
makes a somewhat complicated condition, and one in which 
the interpretation of symptoms might be rendered difficult. 
In this way, if one is not well forewarned of the difficulties, 



Pnmiiive "hranorra^c cepler 
Ti-imltivBhcPm-C. f , in internal capsule; 

pSuorofSri""; po^^-"^^^ circle of primitiye c'enter. 

capsule..' ^ Successive extensions froin ihe center. 




Exi.WaH . 
Ext. CapsuleJ 



jlnterrjal Capsule. 

iCaudaled nucleus of corpus striatum. 



Fig. 24. — Human brain. Section through the atiterior portion of the internal 
capsule, showing the location, mode of formation, and extension of hemorrhages at 
the anterior portion of the internal capsule. {Hetniplegias.) 

they would be tempted (and the error has often been com- 
mitted) to attribute certain symptoms to destruction of some 
one of the gray ganglia, as to the thalamus opticus, or the 



CENTRAL ARTERIES. 8l 

corpus striatum, whicli were only the result of a neighboring 
accident and the incidental compression of the internal capsule. 

The subject is worth further explanations. 

Let us suppose the recent formation of a hemorrhagic cen- 
tre in the lieu cVelection. The blood would then be extrav- 
asated outside of the lenticular ganglion, virtually into the 
space of which we have already spoken ; and the third seg- 
ment of the lenticular ganglion, otherwise called \.\\q putameJi, 
would generally be in part torn away. I have told you that 
under such circumstances the external wall of the extravasated 
spot, including the convolutions of the island of Reil, the ante- 
rior wall, and the internal capsule, would resist the pressure 
of the extravasated blood, while the gray ganglia are gener- 
ally crowded in their entirety towards the ventricular cavities. 
It is clear that the substance of the internal capsule would 
necessarily be more or less forcibly compressed by such a 
change (Fig. 24). Respecting the symptoms produced, two 
conditions might ensue. 

Sometimes the extravasated centre is restricted to those 
portions of the lenticular ganglion which correspond to the 
anterior half or two-thirds of that body ; that is, to the domain 
ot the lenticulo-striated artery. In consequence, the anterior 
part of the internal capsule would be immediately affected by 
compression. The effect would be exclusively a motor hemi- 
plegia of the opposite side of the body (Fig. 22). Sometimes, 
generally extending from before backward, the extravasation 
would crowd to the most posterior parts of the lenticular 
ganglion ; pressure would then be made upon the posterior 
part of the internal capsule, and symptoms of cerebral hemi- 
anaesthesia would follow those of motor hemiplegia. 

Figures 24 and 25 will enable you to easily recognize 
the precise locality, and the mode of formation and exten- 
sion of the various centres of central hemorrhage (see also 
Fig. 23). 

One word more upon the interpretation of these facts. 
After having recognized during life the following symptoms ; 
motor hemiplegia with hemiana;sthesia, and at post-mortem 
the existence of a spot involving the lenticular ganglion, 



82 



DISEASES OF THE BRAIN. 



would you be led to conclude from the close relation of these 
two orders of facts that the lenticular ganglion controlled both 
sensation and voluntary motion of the opposite side ? 

Such conclusion would not be very legitimate, for, had the 
patient survived, and the extravasation absorbed and left as 
a representative only a yellow linear cicatrix, the hemianaes- 
thesia, and even the motor paralysis, notwithstanding partial 
destruction of the lenticular ganglion, would doubtless have 
disappeared, leaving no traces. 



Successive extension 
of primitive center, 

I 



"Rrogressive extension 
.of prtnirtive center. 




'Optic, tkalamus 
Inkmal capsule 

Lenticnuclaia* 
HxtemalcapsulfiL 



'Exi-MH 



Fig. 25. — Human brain. Section through the piisterior portion of the internal 
capsule, showing location, mode of formation and extension of hemorrhages at the 
posterior portion_of the internal capsule. (Hc?niaiicBsihesia.) 



That which has been said respecting hemorrhages of the 
lenticular ganglion applies equally to hemorrhages which oc- 
cur in the posterior portion of the bodies of the thalami op- 
tici. These hemorrhages result from a rupture of the external 
anterior optic, or Icnticulo-optic artery. They are generally 
indicated by a more or less marked hemiplegia, and nearly 
always also by a more or less complete hemianaisthcsia, pro- 
vided the hemorrhage be sufficiently extensive. Should it 



CENTRAL ARTERIES. 83 

be at once concluded (as so many authors have said and still 
repeat) that the thalami optici are the seat of common sensa- 
tion? Incontestably, no; besides, it would be easy to cite 
numbers of facts where a hemorrhagic lesion of the posterior 
tract of the thalamus opticus produced, in the first phase of 
the malady (that is to say, when conditions of pressure existed), 
sensitive and sensorial disturbances, which disturbances ceased 
in the later stage, that is, from the date where reabsorption 
removed the pressure from the posterior or lenticulo-optic 
region of the internal capsule. 

It would be superfluous to continue. I think I have suf- 
ficiently demonstrated that in regional diagnosis, as concerns 
the various parts of the central masses of the brain, it is the 
participation or the non-participation of the anterior or pos- 
terior regions of the internal capsule which determines the 
situation. 

IV. The propositions which I have offered possess a prac- 
tical interest which will not escape your attention. Hitherto 
they have been presented in the form of a postulate. It is 
now proper to establish them by demonstration ; or, in other 
terms, to give you that proof which will serve to insure them 
a permanent place in the records of human pathology. 

We ought also to give, as far as we can, the theory of the 
facts concerned ; that is, we should enter as far as possible 
into the anatomical and pathological reasons. To accom- 
plish this, we are obliged to return once more to the normal 
anatomy of the brain, in order to complete in some respects 
the ideas already acquired. 

In the preceding expose, the predominant role in the patho- 
logical anatomy of the central masses which is sustained by 
the two main departments of the internal capsule, has been 
shown, together with the proof, and they justify the descrip- 
tions which we have made concerning the anatomical consti- 
tution of the grand tract. Now, it is necessary to go a little 
further, and seek for that which is peculiar to the anterior or 
lenticulo-striated region of the capsule, in distinction from 
that which is peculiar to the posterior, or lenticulo-optic re- 



84 



DISEASES OF THE BRAIN. 



gion, where lesions produce only symptoms o{ cerebral Jicmi- 
ancBstJiesia. Wc will commence with the last. 

A. The recent anatom- 



Peduncular fibres, gpingl 
to Corpus striatum ; 

Lenticular nucleus. 



ical researches of Mey- 
- nert have furnished us in 
this respect with very 
important information. 
They have been given in 
detail in a work of one of 
his auditors, Huguenin, 
Professor at Zurich.^ 
They consist of dissec- 
tions and also in compari- 
sons of thin slices, hard- 
ened, and examined by 
transmitted light. 

The brain being placed 
upon its base, the lateral 
ventricles are opened in 
such manner as to lay 
bare the superior face of 
the central masses — those 
which are contiguous to 
the various parts of the 
isthmus ; after that, by 
minute dissection, are 
successively removed : 
1st, tegmcntitm, or upper 
part of the peduncle ; 2d, the tubercula quadrigemina ; 3d, 
the entire thalami optici. 

This being done, the inferior parts of the peduncle {pes, 
crusta) arc brought to view, and higher up (in the region 
of the internal capsule), the fasciculi of peduncular fibres run- 
ning to the caudated ganglion. The fibres belonging to the 
internal capsule, which go to the lenticular ganglion, occupy a 
plane situated beneath and external to the preceding fasciculi. 




Tasiculus^ direct peduncular fibres 
going to cortical substance oi occip'l loBe. 

Fig. 26. — Scheme of direct and indirect pe 
duncular fibres. — {Huguenin.) 



' AUgem. Path, der Krankh., etc., p. 119, Fig. 82, Zurich, 1873. 



CENTRAL ARTERIES. 85 

Attentively observing the internal and posterior parts of 
the diverging fibres thus exposed, there is to be discovered a 
fasciculus, detached as it were from the main body, and which, 
without entering the substance of the gray ganglia, turns 
backward as soon as it reaches the inferior border of the len- 
ticular ganglion (Fig. 26). 

That, you see, is a direct fasciculus, since the fibres of which 
it is composed enter the diverging fibres without stopping in 
the gray substance of the central masses ; it is, moreover, as 
the description shows, a separate fasciculus. 

What is the destination of these nerve-fibres? With man 
it is nearly impossible to say ; but in some monkeys, accord- 
ing to Meynert, their course can be easily followed into the 
body of the white substance of the occipital lobe, just outside 
the posterior cornu of the lateral ventricle {comic posteriiis, 
ventriculi lateralis). They finally terminate in the body of 
the gray cortical substance of the occipital lobe. 

B. Does there exist any anatomical reason for supposing 
that the fasciculus in question is really composed of centripetal 
fibres, having as a function the transmission of sensitive im- 
pressions to the surface of the posterior regions of the brain ? 
Meynert so thinks, and for the reason that (according to him) 
these fibres, by comparing thin slices, can be followed down 
the length of the cerebral peduncle to the protuberance 
(foot, inferior part) ; in the peduncle they occupy the most 
external part. Reaching the protuberance, they go to the 
posterior part of the pyramidal fasciculus, and maintain very 
nearly the same location in the anterior pyramid to the point 
of decussation. There (contrary to that which occurs with 
the most internal fasciculi of the pyramid, which pass into 
the lateral columns of the spinal cord) they decussate, and 
then join the posterior spinal fasciculi. I am not able to guar- 
antee the entire authenticity of the last part of the tract as- 
signed by Meynert to the fibres which compose the most pos- 
terior portion of the internal capsule. 

Such is at present the share of normal anatomy, and it 
affords an independent illumination of our subject. But how- 
ever important this aid, it would, without pathological anat- 



86 DISEASES OF THE BRAIN. 

omy and experimentation, be entirely insufficient to solve 
the problem ; and once more we repeat that physiology and 
pathology cannot be deduced from an unassisted contempla- 
tion of pure anatomical facts. 

C. We are now at the proper point to introduce clinical and 
anatomico-pathological proofs. At the present time they are 
abundant. It will suffice to note the observations of Ludwig 
Tiirck, the pioneer in this road/ those of his compatriot 
Rosenthal," those which I have collected at the Salpetriere, 
and finally those which have been gathered by Veyssi^re 
and Rendu, the first in his inaugural thesis,^ the second 
in his thesis for agrcgation^ 

The comparison of these observations gives the following 
uniform results: 1st, that lesions confined to the posterior 
lenticulo-optic region of the internal capsule necessarily result 
in that form of hemianaesthesia which I call cerebral, and in 
which sensations controlled by the cerebral nerves, that is, 
the optic and olfactory nerves, are so affected as to faithfully 
reproduce the characteristics of hysterical hemianjEsthesia ; 
2d, that on the contrary, in all cases where the lesions involve 
only that part of the capsule which lies between the lenticular 
ganglion and the head of the caudated ganglion, anaesthesia 
is absent. 

These contributions of pathological anatomy and clinic are 
by themselves of incontestable and prime importance ; but 
combined with the testimony of pure anatomy, they assume 
a standard value. 

That is not all ; experimentation has in turn brought its 
share of facts, which also repeat the same story. 

Under the guidance of pathological knowledge, experi- 
mentation has corrected itself. It had previously been sup- 



' Tiirck, see Charcot. — Lectures upon Maladies of the Nervous System, t. I., ad 
ed., p. 315. 

"^ Rosenthal, Klinik der Nervenkranklieiten, 2d Aufl., Stuttgart, 1875. 

^ R. Veyssiere, Recherches cliniques et experimentales sur I'liemianesthesie de 
cause cerebrale. These de Paris, 1S74. 

* H. Rendu, Des anesthesies spontanees. These d'agregation, Paris, 1S75, pp. 
27 and 95. 



CENTRAL ARTERIES. 



87 



Lenticular nucleus"^ 
\\';2 Section of ant. porliorf, j 
of internal capsule ; ; ^ 
Cauda led nviclei 
A of corpora ^striata. 




posed that the centre of sensitive impressions was not in the 
brain proper, nor in the thalami optici, but lower down, in 
the protuberance, or perhaps in the crura cerebri. 

Pathology controverted 
that assertion, in showing 
that a lesion situated above 
those points, in certain re- 
gions of the brain itself, was 
quite sufficient to invariably 
produce a total hemianaes- 
thesia. Recent experimental 
researches made by Duret 
and Veyssiere, in the labor- 
atory of Vulpian, have given 
results also in conformity 
with pathological teaching. 
An ingenious instrument, 
consisting of a trocar from 
which at a desired moment 
escapes a spring, is intro- 
duced through the cranial 
wall into the central masses, to a depth and in a direction 
calculated through previous experiments. Thus, with a little 
experience, either of the two portions of the internal capsule 
can by itself be injured. 

If in these experiments the lesion reaches the posterior 
capsule, hemianaesthesia of the opposite side of the body 
certainly ensues ; generally there is associated with it a cer- 
tain degree of motor paralysis ; this (motor paralysis), on the 
contrary, occurs unaccompanied with anaesthesia whenever 
the lesion is confined to any point of the anterior two-thirds, 
leaving the posterior third of the internal capsule untouched. 
(Figs. 27 and 28.) 

Such in brief are the substantial results of these experiments. 
After the foregoing, you will see that everything concurs to 
establish the existence of direct fasciculi of centripetal nerve- 
fibres in the posterior part of the internal capsule, having for 
function the conduction of sensitive impressions coming from 
the opposite side of the body towards the centre. 



Inl.capsulej / ; Xj'Int.capsuU 
Cliiasma of optic nerves ^ 

Fig. 27. — Transverse section of a dog's 
brain, five millimetres anterior to the optic 
chiasma. 



88 



DISEASES OF THE BRAIN. 



Emanating from the foot of the central peduncle, these 
fasciculi, as they leave the capsule, run directly towards the 
formation of the diverging fibres, without communicating 
with the gray ganglia of the central masses. Near their ori- 
gin, that is, at the inferior part of the capsule, these fasciculi, 
pressed into a narrow space^ might be affected in great num- 

Caudat^d nuclei 

Int" capsule, 'post porlion. 




Horns'„ 
of-AmnioiL 



S cct.ui p'u i>t . part 
of intl. capsule 



Fig. 28. — Transverse section of a dog's brain, on a plane with the tubercula mam- 
millaria, — ( Carville and Duret. ) 

bers by a single stroke, by a very minute lesion, and be fol- 
lowed by very marked anaesthesia. It can be understood, on 
the other hand, that higher up, on a level with the foot of 
the diverging fibres, a lesion of the same extent would, by 
reason of the divergence of the fibres, produce much less 
marked effects. This is, in fact, the case. There exist many 
examples of well-marked hemianaesthesia in connection with 
slight lesions of the foot of the diverging fibres. 

It should now be determined if lesions extended to the 
occipital lobes, and especially to their gray cortex, produce 
crossed hemianaesthesia. Unhappily the facts which can be 
cited in that regard are not sufficiently explicit, and the ques- 
tion must remain in suspense until more ample information 
is obtained.' However that may be, it is now recognized 

' In the observations which I have collected of superficial softenings of the 
occipital lobe, there were frequent hyperassthesias, painful sensations of all sorts 
in tlie opposite limbs, hallucinations of vision, etc., as well as heniiansesthesia or 
amblyopia. 



CENTRAL ARTERIES. 89 

that the fascicuH which compose the posterior part of the in- 
ternal capsule, and their direct emanations, cannot be con- 
sidered as a centre of sensitive and sensorial impressions. 
These fasciculi can only represent a highway, a cross-road, 
where the centripetal fibres of which it is composed are all 
represented before diverging to the superficial parts of the 
brain. 



TENTH LECTURE. 



CEREBRAL HEMIANESTHESIA (Continued).— CROSSED AM- 
BLYOPIA.— LATERAL HEMIOPIA. 



Sumniary : — Rcsniiie of tlie Characters of Ccrehral Hemiansesthegia. — 
Its Resemblance to Hysterical Hciniaiicestliesia. — Aiit«stliesia In- 
volves General Sensibility in its Various Forms, and also tlie Special 
Senses.— Hysterical Amblyopia. — Oplitlialmoscopic Examination. — 
Concerning Functions. — Diminution of Visual Acuteness. — Concen- 
tric and General Contraction of the Field of Vision, etc. — Crossed 
Amblyopia '\vitli Hemianrcstliesia from Cerebral Causes.— Symptoms. 
— Lesions of the Cerebral Hemispheres wbicU Produce Hemianresthe- 
sia Produce also Crossed Amblyopia and not Lateral Hemiopia. — 
Hemiopia. — Hypothesis of Semidecussation. — ^Unilateral Homologous 
Hemiopia. — Varieties of Hemiopia. 

Gentlemen : 

In the last lecture I attempted to prove that a peculiar form 
of hemianaisthesia is a necessary consequence of lesions in 
the posterior regions of the internal capsule, or of its emana- 
tions in the diverging fibres, no matter whether these lesions 
be destructive, compressive, or suspensive, the value of which 
last term I will soon explain. 

I have based this proposition not alone upon pathological 
apd clinical anatomy, but also upon the facts of experimenta- 
tion. I have given, too, some contributions from pure anatomy 
which, to be sure, in certain respects, require confirmation, 
but such as they now are, they permit us to look into the 
mechanism by which the hemianaisthesia in question is pro- 
duced. 

There are some features relative to the totality of symptoms 
and their anatomical and physiological interpretation, that I 
have purposely left in shadow, so as not to overcrowd the 
picture. I propose now to recur to them. 



CROSSED AMBLYOPIA. — LATERAL HEMIOPIA. 91 

I. First, let me in a few words recite the clinical characters 
of that kind of hemianaisthesia which I propose to call cere- 
bral hemiancBsthesia, in order to distinguish it from all other 
forms of obscuration or diminution of sensibility, the origin 
of which is not recognized as depending upon a lesion of the 
brain proper. 

It is only lately that cerebral hemianaesthesia from gross 
organic lesion — " coarse disease," as H. Jackson, with a lib- 
erty quite English, terms it — has been the object of attentive 
study. The picture it presents is exactly that of hysterical 
hemianaesthesia ; this last, being at present better known, 
will more naturally serve as a prototype. 

Hysteria, you know, presents a unilateral anaesthesia. 
Total anaesthesia is relatively rare. An antero-posterior plane 
through the median line of the body marks the limit of insen- 
sibility, which line upon the trunk, however, is somewhat 
overstepped on the sternum in front, and on the spinal crest 
behind. This is a detail of secondary importance. 

The head, the limbs, and the body on one side, then, are 
all affected at the same time. There may naturally be de- 
grees in the functional disturbance, but more frequently it 
embraces all kinds of common sensibility ; the sense of touch, 
of pain, and of temperature are often simultaneously obscured 
or suppressed. 

The insensibility extends to the profound parts ; it affects 
the muscles, which may be electrically excited without the 
patient's consciousness of it. The mucous membranes are not 
spared. Finally, let us add — and this is the point which 
above all others I just now desire to make prominent — hemi- 
anaesthesia does not include common sensation alone, it in- 
volves also the sensorial apparatus of the same side of the 
body affected with cutaneous anaesthesia, and that sensorial 
heniiancesthesia takes in, not only the nerves coming from 
the bulb, such as those of taste and hearing, but also the 
nerves of smell and vision, the origins of which are in the 
brain proper. 

Such is the common picture of the hemianaesthesia of hys- 
teria. If we compare the hemianaesthesia really cerebral 



92 DISEASES OF THE BRAIN. 

with this, we will see a perfect resemblance, even to the 
smallest detail. 

We have already carefully brought to light the resemblance 
as concern^ common sensation,^ and Magnan has done the 
same in that which concerns troubles of hearing, smell, and 
taste.^ I see nothing to add to what has been said upon the 
subject. Lately we have been more particularly occupied 
with those phenomena which concern vision. In my service 
at Salpetricre, Dr. Landolt has devoted himself to researches 
in that direction, the results of which merit brief mention. 

It seems to me of interest to offer some facts showing that, 
even as relates to visual troubles (and this you will soon rec- 
ognize as of great consequence), absolutely the same things 
occur in real cerebral lesions as with those simply hysterical. 
Abstraction seems to exhibit here its proverbial changeabil- 
ity ; the unilateral amblyopia of hysterics differs in no essen- 
tial character from the crossed cerebral amblyopia recognized 
as having an organic origin. 

Let us first examine hysterical amblyopia. 

IL 1st. Here diminution more or less pronounced, and 
sometimes (though rarely) absolute loss of vision upon the 
side corresponding to the hemianaesthesia, is the first easily 
recognized symptom, 

2d. A more minute study develops the following peculiar- 
ities : There exist in the bottom of the eye no alterations 
appreciable by the opthalmoscope. The pupil and retina are 
entirely normal. Comparative examination of the posterior 
portions of the two eyes shows also no appreciable difference 
in their vascularization. 

If the ophthalmoscope does not betray alterations in ani- 
hlyopia of hysteria, it is not the same with subjective func- 
tional phenomena. This is what is learned through that 
method of examination. 



' Charcot. — Lectures upon Maladies of the Nervous System, ist ed., 1872. 
^ Magnan. — Upon Ilemianxsthesia of General Sensibility and of the Special 
Senses in Chronic Alcoholism. Gaz. hebd. , 1873, pp. 729 and 746. 



CROSSED AMBLYOPIA.— LATERAL HEMIOPIA. 93 

3d. Visual aciitencss, studied after ordinary rules, often 
shows itself reduced by one-half or even more. 

4th. There exists d. general and concentric contractioti of the 
field of vision. 

5th. Careful analysis has recognized certain peculiarities 
which deserve attention ; they concern the concentric and 
general contraction of the field of vision for colors. 

Many authors, among others Galezowski, have heretofore 
remarked the frequent accompaniment of achromatopsia and 
dyschromatopsia with hysteria. These are the special points 
of observation made in my service by Landolt. 

I would recall to you that in the normal state, all regions of 
the visual field are not, for some reason, equally apt in percep- 
tion of colors. There are colors for which the visual field is 
physiologically more extended than for others, and these 
differences in the extent of the visual field always occur in 
the same subject according to the same law for each color. 
Thus the widest field of vision is for blue ; then yellow, then 
orange, red, green, and lastly violet, which is only perceived 
by the most central parts of the retina. Now, in the patho- 
logical condition with which we are occupied, the normal 
condition exists, though in various degrees exaggerated. 
Indeed the various circles which in this investigation corre- 
spond to the limits of vision for each color, are contracted 
concentrically in a more or less marked manner, but still 
based upon the law recognized for the normal state. 

From this you can easily foresee the numerous combinations 
which may arise in cases of hysteria where this kind of am- 
blyopia has attained a high degree. The violet circle may 
contract to nothing, then as the malady advances the same 
will occur consecutively with the green, red, and orange ; 
the yellow and blue remain to the last ; observation demon- 
strates that these are the two colors for which sensitiveness 
is longest preserved in cases of hysteria. Finally, in extreme 
cases, it may happen that perception of all colors ceases, and 
then to the eyes of the patient colored objects would all be- 
come reduced to the appearance of a sepia drawing. 

Such is the series of phenomena which we have over and 



94 DISEASES OF THE BRAIN. 

over observed in hysterical amblyopia. Now, these are all 
met with in their different shades, in various cases of crossed 
amblyopia accompanied with hemiana^sthesia and arising 
from a lesion in the centre of the brain, such as we have re- 
cently examined. The same is true of diminution of visual 
acuteness ; of concentric and general contraction of the visual 
field of colors, even where no pathognomonic lesions at the 
bottom of the eye are appreciable with the ophthalmoscope, 
etc.^ 

I insist especially upon this last characteristic, because it 
permits a clear separation of the functional trouble from those 
usually caused by intercranial, organic lesions. I allude to 
the alterations at the bottom of the eye, easily discovered 
■with the ophthalmoscope, and commonly known under the 
name oi papillary stranglmg or nenro-retinitis, and which is 
so frequently seen as a consequence of encephalic tumors, 
whatever may be their nature or location^ and also following 
various lesions acting more or less directly on the optic 
bands. 

In making known to you that crossed amblyopia is a con- 
sequence of lesions within the brain, I have stated a fact of 
major importance for the theory of cerebral localization. But 
it cannot escape you that this fact is in formal contradiction 
to generally diffused ideas. Indeed, if the theory put forth in 
i860, by Alb. de Graefe,^ and which still appears to hold un- 
divided sway, as witness an interesting work recently pub- 



' New researches made for me by Landolt have demonstrated that contraction 
of the field of vision for colors, in ovarian hysteria with hemianesthesia, is always 
experienced in both eyes at the same time ; only it is incomparably more pro- 
nounced in the eye corresponding to the side affected with the anaesthesia. The 
same peculiarity is encountered in all cases, which have been examined in this re- 
spect, of cerebral hemiaficcsthesia arising from organic lesions. Therefore the 
term crossed amblyopia^ used in these lectures, will not be taken as absolutely 
literal, since the obscuration of sight affects, unequally to be sure, both eyes. 

^ See upon this subject the interesting work of Dr. Annuske. — Die Neuritis 
Optica bei Tumor Cerebri^ in Arch, fur Ophthalmologic, 19 Bd., Abth. III., 

1873. P- 165- 

^ A. de Graefe. — Gazette hebdomadaire, i860, p. 708. See, also, Vortrage aus 
der V. Graefe'schen Klinik. Monatsbl. f. Augenhlkde., 1865, Mai. 



CROSSED AMBLYOPIA.— LATERAL HEMIOPIA. 95 

lished by Dr. Schoen,^ be credited, it is not crossed amblyo- 
pia which determines exckisively unilateral lesions of the 
brain, but a different visual trouble, namely, lateral Jiomol- 
ogous Jicniiopia ; in other words, a cerebral lesion of the left 
substance of the brain should, according to the theory in 
question, produce suppression or obscuration of the right 
half of the visual field, and the reverse in case of a lesion in 
the right half of the brain. 

I believe that I can protest against this theory as being at 
least too absolute, and I offer against it the following propo- 
sition : cerebral lesions of the Jiejiiispheres zvJiicJi produce henii- 
ancBSthesia produce also crossed amblyopia, and not lateral 
he miopia. 

I am not prepared, let it be well understood, to decide that 
lateral hemiopia is never the consequence of a lesion in the 
substance of the brain, but I am disposed to believe that 
such cases, if they really exist, are phenomena of contiguity — 
the effects, for example, of a more or less direct participation 
of the optic bands. I do not believe that there now exists a 
single observation clearly showing, except in this way, the 
development of lateral hemiopia as a consequence of a lesion 
of the posterior part of the internal capsule or the foot of 
the diverging fibres, while a number of facts exist where such 
a lesion has produced crossed amblyopia with all the charac- 
teristics that we have just assigned to it. 

III. We must give some details relative to the symptoms 
of hemiopia and the presumed anatomical cause of its develop- 
ment. 

You know that this singular phenomenon, so often observed 
in clinic, has long since suggested an anatomical hypothesis 
according to which the optic nerves in man do not make a 
complete decussation in the optic chiasma, but that which is 
called a semidecussation. That hypothesis is an old one. It is 
generally attributed to WoUaston, but it is really due to Nezv- 
ton, who expressed it in 1704, in his Treatise upon Optics^ and 

' Schoen. — Archiv der Heilkunde, 1875, ist Heft. 



96 DISEASES OF THE BRAIN. 

which Vater, in 1723, employed to explain three cases of hemi- 
ppia which had fallen under his observation.^ I will recall the 
hypothesis. 

Among the nerve-tubes which form the bands of the optic 
nerves there are those which, as has been said, decussate 
in the chiasma and those which do not. (See Fig. 29.) 
These last, that is, the non-decussating nerve-tubes, occupy 
the external sides in the bands, in the chiasma, and also in the 
optic nerves and the retina, whereas at all of these points the 
fasciculi which decussate occupy the internal sides. It follows 
that the non-decussating fasciculi, of the left band, for example, 
being affected, would affect the left half of the retina of the 
left eye, while the decussating fasciculi of the same band would 
affect the left half of the right eye, the fasciculi of the right 
optic bands operating of course after the same principle in- 
versely. 

In other words, the fasciculi which compose the optic band 
of the left side would go to the left half of each retina, and 
the reverse would occur with the nerve-fasciculi coming from 
the optic bands of the right side. 

It must be remembered that anatomically speaking this 
arrangement of the optic nerve-fibres is entirely hypothetical. 
If, indeed, various authors, among others Hannover,^ Longet, 
Cruveilhier, Henle,^ and more recently Gudden,^ have thought 
themselves able to offer anatomical proof, there are others, 
such as Biesiadecki," E. Mandelstamm,'' and Michel,'' who con- 
tradict it, and appealing to the same order of arguments 

' Knapp. — Archives of Scientific Medicine, New York, 1872. 

^ Hannover. — " Das Auge," Beitiage zur Anatomic, Physiologie, und Patholo- 
gic dieses Organs, Leipzig, 1872. 

^ Henle. — Nervenlelire. Ueber die Kreutzung im Chiasma Nervorum Optico- 
rum. 

* Gudden. — Arch, fiir Ophthalmologic, 1874, t. 20, 2d Abth. 

' E. Biesiadecki. — Ueber das Chiasma Nervorum Opticorum des Menschen und 
der Thiere. Wiener Sitzber, d. math. Naturwiss. Classe B., d. 42 Jahrg. 1861, 
p. 86. 

* E. Mandelstamm. — " Uel^er Sehnervenkreuzung und Ilemiopie." Arch, fiir 
Ophthalmologic, t. 16, 1S73, p. 39. 

' Michel. — Ueber den Bau des Chiasma Nervorum Opticorum. Same work, p. 
59, Taf. I., Fig. IV. See also Bastian, The Lancet, 1874, July 25, p. 112. 



CROSSED AMBLYOPIA. — LATERAL IIEMIOPIA. 



97 



attempt to demonstrate that the nerve-fibres of the optic 
nerves, even in man, submit to a complete decussation. In 
short, it may be said that at present the question is far from 
being settled. I repeat that the semidecussation is only 
an hypothesis ; but that hypothesis explains, far better than 
any of its substitutes, all the facts observed in clinic. In the 
scheme herewith given it will be seen hov/ easily it serves to 
interpret the various modes of hemiopia. (Fig. 29.) 



S'emi-decussalion in diiastna.i 
XesionKere would produce temporal hemiDpiaJ 

Hires decussating in-chiasma'^., ! 



'JTon-decussating fibres in diiasma.. 



I es'iortliere .pro duces nasal hemiopia' 



Lesion of opiic iancf. 
producing right Idteral 
liemiopia. 



a. 



Genicular iodj 



left heraispliere. Lesion. ' 
here would produce crossea^^ 
light amblyopia^. \n 




•"JiliresfrolTi rigKt eye 
runningto lefl lieimsphere 



tLesIon-iere .produces Tiasal "hemiopia 



Tibres from rigw: '-j 
eye , ending in left nemisphere 



(knicular iociy: 



iK^t liemispliere. 
'DecussationLack. of genicular todies. 



Fig. 29. — Scheme to explain the phenomena of lateral hemiopia and crossed am- 
blyopia. 

We will first consider unilateral homologous hemiopia, that 
which, according to writers, can occur only as the direct con- 
sequence of an intracerebral lesion of the brain. It is clear 
that according to the theory, a lesion situated at 5 in such 
way as to interrupt the tract of the fasciculi of the left optic 
band, those fibres which crossed in the chiasma {d), and also 
7 



98 DISEASES OF THE BRAIN. 

those which did not cross (a), would result in afiecting the left 
half of each retina {II), in other words, might obscure or 
completely suppress the entire extent of the visual field of the 
right side {lateral right hemiopia). Lateral left Jieniiopia 
would ensue from a lesion affecting in the same manner the 
optic band of the right side. 

Thus speaks theory ; as for facts, there are numerous ex- 
amples which demonstrate that lateral hemiopia is really the 
consequence of a lesion bearing upon one of the optic bands.^ 
The effect will remain th^e same, no matter upon what part 
of the band, between its origin in the genicular body and its 
termination in the chiasma, the lesion occurs. Lateral hemio- 
pia may also be produced not only by a lesion in the band 
itself, but also as a contiguous phenomenon in consequence 
of lesions— hemorrhage or tumors — developed in parts which 
are in more or less immediate relation with the tract, such, for 
example, as the lower part of the cerebral peduncle {pes) or in 
the pulvinar. 

Other modes of hemiopia are not difficult to interpret. A 
lesion, a tumor, for example, situated at (3), that is, upon the 
median part of the chiasma in such way as to involve only 
the decussating optic fibres {c, d) might paralyze the left 
(i) half of the retina of the right eye as well as the right half 
(2) of the retina of the left eye, and so produce what is called 
temporal hemiopia. Saemisch foretold, in a case of this 
kind, while the patient still lived, that such was the location 
of the lesion, and autopsy fully justified his prediction.^ 

On the contrary, that hemiopia, called nasal, characterized 
by the suppression of the median portion of the field of vision, 
would be produced if the course of the direct fibres {a, b) 
only were interrupted, at the chiasma, for example, in conse- 
quence of lesions occupying each side symmetrically at the 
points (4, 4). This is a combination which is indeed rare. 
There exists, however, some examples ; among others one 



' See, among others, the case of E. Muller in the Arch, fiir Ophthalmologie, 
VIII. Band i, S. 160. 

* See also E. Muller in Meissner's Jahresbericht, 1861, S. 45S. 



CROSSED AMBLYOPIA. — LATERAL HEMIOPIA. 99 

carefully described by Knapp.^ In this case it resulted from 
a pressure upon the points indicated, by the anterior cerebral 
arteries and the posterior communicant artery enlarged and 
indurated by an atheromatous degeneration. 

I will dwell no longer upon these forms of hemiopia, which 
do not at present directly interest us, but return to lateral 
hemiopia. It seems an established fact that this visual trouble 
is the necessary result of a lesion of the optic bands ; it is 
also generally affirmed to be the necessary consequence of a 
lesion which may affect the optic nerve-fibres beyond the 
corpora geniculata (7) in their deep intracerebral tract (in 8, 
9). In my opinion, clinical and pathological anatomy con- 
tradict that assertion — at all events, when made in too absolute 
a manner ; and in this respect I can but repeat that which I 
just now have said ; I do not believe that there now exists 
a solitary observation showing, beyond doubt, the develop- 
ment of lateral hemiopia in consequence of an intracerebral 
lesion outside of all participation of the optic tracts, whereas 
facts exist where a lesion of the posterior part of the internal 
capsule, or the foot of the diverging fibres, has produced 
hemiansesthesia, and at the same time crossed amblyopia, a 
visual trouble very diverse from hemiopia. 

That being the case, how can we understand, in a sche- 
matic view, that effect of a cerebral lesion, while at the same 
time we recognize the incontestable fact of hemiopia being 
the consequence of a lesion of the optic bands ? 

To this end a slight modification of the common scheme 
will suffice. It is generally admitted that the nerve-fibres 
coming from the right eye and the left eye which compose 
each of the optic bands continue their course beyond the 
corpora geniculata uninterruptedly into the very depths of the 
corresponding hemispheres, and that view accords with the 
prevailing idea that a lesion of the optic nerve-fibres in their 
intracerebral course is equivalent to a lesion of the optic 
bands, and consequently produces hemiopia. 

I propose to admit, on the contrary, that only the fasciculi 

' Arch, of Scientific and Practical Medicine, 1S73, p. 293. 



lOO DISEASES OF THE BRAIN. 

of the bands which decussate in the chiasma {c, d) reach their 
profound depths, whatever they may be, without new decus- 
sation ; whereas the direct fasciculi do completely decussate 
beyond the corpora genicuiata, before entering into the 
depth of the hemispheres (8, 9) ; this occurs upon an undeter- 
mined point of the median line, perhaps in the tubercula 
quadrigemina. From that arrangement it would result that 
the fasciculi (3, d), reunited, for example, in a point of the 
left hemisphere (8), would represent the totality of the fibres 
coming from the retina of the right eye, and that the fasciculi 
{a, c) would represent the totality of fibres coming from the 
left eye. The optic fibres, according to that, in their pro- 
found course, are at length all reduced to the type of com- 
plete decussating fibres, and one can comprehend that, in an 
apparatus so constructed, a lesion of the optic bands would 
produce lateral hemiopia, although a lesion situated deeply 
in the substance of the brain would to the contrary produce 
crossed amblyopia. 

I give you this hypothesis for whatever it is worth. At 
present it has no anatomical base. But at all events it fur- 
nishes, if I am not deceived, an easy means of very simply 
representing the tolerably complex facts revealed by clinical 
observation. 



ELEVENTH LECTURE. 

ORIGIN OF THE CEREBRAL PORTION OF THE OPTIC 

NERVES. 

Samniary :— Relations of Crossed Amblyopia and Sensitive Hen»i- 
ansestliesia. Resulting from a Lesion of the Internal Capsule.— 
Cerebral Origin of tlie Optic Nerves.— Diverging Fibres of Reil. — 
Radiating Cortico-optic Fasciculi. — Anterior Fibres (Anterior Roots 
of the Tlialami Optici) ; 3Iiddle Fibres (Lateral Expansion) ; Poste- 
rior Fibres (Cerebral Expansion of the Optic Nerves) ; Anatomical 
Relations bet^veen the Cerebral Expansion of the Optic Nerves and 
the Centripetal Portions of the Radiating Fibres (Sensitive Hemi- 

anccsthesia). — Optic Bands Origin of the External Root (Thalaini 

Optici); External Geniculate Bodies, Anterior Tubcrcula Q,uadri- 
gemina. — Origins of the Internal Root (Intei-nal Geniculate Bodies, 
Posterior Tubercula Q,uadrigemina). — Relation bet-ween the Mass 
of Gray Substance and the Gray Cortex of the Enceplialon.— Cortico- 
optic Radiating Fasciculi.— Effects of Lesions of the Anterior Tu- 
bercula Q,uadrigemina. — Facts of Lateral Hemiopia of Supposed 
Intra-cerebral Origin. 

Gentlemen : 

I hope that I have demonstrated the existence of crossed 
amblyopia as a symptom of lesion in the posterior part of the 
internal capsule, or of the corresponding irradiations of the 
foot of the diverging fibres. 

At the same time I have attempted to prove de Graefe's 
proposition, that homologous hemiopia might be (crossed 
amblyopia excluded) the only functional trouble of vision 
following a lesion of the cerebral hemispheres, to be at least 
too sweeping, and that the arguments upon which it rests 
ought to be completely revised. 

I now wish to examine whether normal anatomy can ex- 
plain why the sensorial trouble in question, that is, crossed 
amblyopia, is a frequent, as it were habitual, accompaniment 



I02 DISEASES OF THE BRAIN. 

of sensitive hcmianaesthesia resulting from a lesion of the in- 
ternal capsule. 

This hemianjesthesia of common sensibility, you remember, 
may be produced through the existence of a fasciculus of 
direct centripetal fibres, that is, fibres not stopping in the 
gray ganglia of the central masses, and which, upon issuing 
from the internal capsule, form the very posterior portion of 
the diverging fibres. 

Does there exist a connection, a more or less immediate 
relation, between that sensitive fasciculus and the sensorial 
fasciculi designed to put the apparatus of vision in communica- 
tion with the gray cortex of the brain ? To enter upon this 
question it is first necessary to study the origin of the pro- 
found or cerebral part of the optic nerves. We will examine 
this difficult subject, which is still obscure in more than one 
point. I must not, however, omit giving you the principal 
outlines, if only to indicate the direction in which our future 
researches should be made, and where pathological anatomy 
will very likely be called to play a dominant part. 

According to the general plan, the encephalic nerves ought 
to encounter, before penetrating the brain itself, one or more 
masses of gray substance, which it is agreed to call the gan- 
glions of origin^ and the expansions arising from these ganglia 
put these nerves in an indirect rapport with the gray cortex 
of the cerebral hemispheres. 

A priori, there is nothing to induce belief that the optic 
nerves escape the rule. In fact, they do not escape it, but 
their distributions are very complicated and ill-known, espe- 
cially in some of the details. 

I. I will pause an instant to note the construction of a por- 
tion of the diverging fibres of Reil.^ 

' The various fasciculi, peduncular or otherwise, which form the diverging fibres, 
{fibres convergentes of Luys) (systinie de pi-ojection de V ordre oi Meynert) com- 
pose the greater portion of the white central mass called centrum ovale, which the 
gray cortex of the hemispheres envelops and encloses like a purse. They, how- 
ever, do not represent the totality of that mass. It contains, beyond these, fasci- 
culi entirely foreign to the preceding, but which mix with them. These last fasci- 
culi constitute that which Meynert calls the system of association. One may 
distinguish in a general way the two orders of fasciculi which compose this system. 



CEREBRAL PORTION OF THE OPTIC NERVES. 



103 



In the scheme which I present to you and which is bor- 
rowed from Huguenin (loc. cit., pi. 69, page 93), the ablation 



3''-^?e^ineut of lent.nudeus. 
PiLeis uniting two convols. 1 



Tasicukis aTctiatu; 




Tasidulu^ Jong'itiid.ir/. ' / 
■ Piilvinar.' 

EoTTi of Ammon 
ExLerrLCorpora geaiculata' 



Posihcm o'f lat.yentacle. 
Caudate dezlr. of corpus slriatum. 



Fig. 30 — Antero-posterior section of a monkey's brain [Cercocebiis chiomolffus) 
showing the connecting fibres of the brain. — {Meynert, Strieker's Hand-book.) 

of the superior parts of the hemispheres, including the corpus 
callosum, has laid bare the ventricular cavities. You will 



One kind consists of commissures which unite the homologous parts of the two 
hemispheres. Such, for example, are the corpora callosa and the anterior com- 
missure. The others are composed of fibres having a general antero-posterior 
direction, which bring into relation the various points of the same hemisphere. 
Fig. 30, borrowed from Meynert (loc. cit., Fig. 233), representing the anterior 
section of the brain of a monkey {Cercocebiis cinoinolgns), very well exhibits the 
direction of the principal fasciculi of the antero-posterior system of association. 
There are to be seen the fibres uniting two convolutions {fibres propria')^ well 
described by Gratiolet, ih.^ fasciculus arciiattis, the fibres of which extend beneath 
the corpus callosum from the occipital to the frontal lobe ; the inferior longitudinal 
fasciculus which joins the occipital lobe to the extremity of the sphenoidal lobe, and 
finally, the fascicubis tmchiaius ^ which runs nearly vertical and which joins the 
frontal to the sphenoidal lobe. 



104 



DISEASES OF THE BRAIN. 



notice particularly the inferior part, or the posterior cornu of 
the ventricle which here plays an important role in topogra- 
phy (Fig. 32). 



Hbres of Optic thalamus 
ezUnding to the periphery 



Caudated nucleus 



Fibres of caudated nucleus 
extending toithe periphery 



Direct 
fibres. 




Fig. 31. — Scheme illustrative of the different orders of peduncular fibres. — {Huguc- 
nin. ) 

The caudated ganglion has been detached and its outlines 
are represented by a dotted line ; its diverging fibres, that is 



CEREBRAL PORTION OF THE OPTIC NERVES. 105 

to say, the plane of the cortico-striated radiating fibres, have 
also been removed. Thus is uncovered the plane of the cor- 
tico-optic radiating- fibres. In these last fasciculi it is possible 
to distinguish three groups of fibres : ist, the anterior ones 
called anterior roots of the thalami-optici (Vordcre Stiel), they 
are directed towards the frontal regions ; 2d, others are mid- 
dle or lateral ; 3d, and finally, the posterior ones are desig- 
nated by Gratiolet, who first ^ well studied them, under the 
name of optic cerebral expansions, or expansion of the optic 
nerves {SeJistraJihuigen). The fasciculi of the last group, 
which are the special object of our study, are separated from 
the cavity of the posterior cornu only by the ependymus and 
the tapetum, a special expansion of the splenium of the corpus 
callosum. 

It is in this same region, but on a deeper plane, that the 
cerebral expansions of the fasciculi of centripetal fibres are 
spread, the lesion of which produces sensitive hemianaesthe- 
sia of cerebral origin. There exists, then, a relation of pro- 
pinquity, of contiguity, between these fasciculi and the optic 
expansions, and that relation would well explain anatomi- 
cally the frequent coexistence of hemianaesthesia and crossed 
amblyopia if it could be well established that those fasciculi 
which bear the name of optic expansions are really a more or 
less direct prolongation of the optic nerves. 

II. We will make a little digression upon this point in 
order to ascertain what is known about the gray ganglia at 
the base of the encephalon, outside of the brain proper, where 
the optic nerves originate. 

Here it seems proper to examine the exterior architecture 
of the parts which we are about to consider. 

After detaching the entire isthmus from the encephalon, 
leaving attached the thalami optici, an examination of the 
posterior face of the preparation thus obtained will discover 
as follows : ist, anteriorly, on each side, are the thalami op- 
tici, which separate the third ventricles ; 2d, posteriorly, the 

' See Gratiolet, Anat. comparee, t, II., p. iSi et suiv. Luys, loc. cit., p. 173. 



io6 



DISEASES OF THE BRAIN. 



tubercula quadrigemina, both anterior and posterior ; 3d, 
externally, the anterior conjunctive fibres connecting by their 
internal extremities with the anterior tubercula quadrigemina, 



Corpus 
EtriatujTi-- 



Arch.and 
three pillars' 



Corpora /. 
quadngeiTiina 

Horn of Ammon' 
Jbst-.iiDni of Idt, 



Ant. root of 
Optic thalamus , 




lond 



adiations of 
Grdtiolet.(optic) 

Fig. 32. — Radiations from the thalamus opticus. — {Huguctihi.) 



the posterior conjunctive fibres connecting with the posterior 
tubercula quadrigemina. Then, in the same region, by raising 
the posterior extremity of the thalami optici, or pulvinar, 
maybe seen, internally, the internal geniculate body, and ex- 



CEREBRAL PORTION OF THE OPTIC NERVES. 10/ 

ternally, a gray mass, somewhat more voluminous, which is 
the external geniculate body. 

Behind and above these parts are to be seen the loop of 
Reil, the processus ccrebclli ad testes, the cerebral pedun- 
cles, the restiform bodies, and the middle cerebral pedun- 
cles. 

The internal and external geniculate bodies are notably the 
first two ganglia of gray substance with which the optic nerves 
enter into rapport on their way to the encephalon. The optic 
nerves posterior to the chiasma take the name of optic tracts, 
or optic bands, and in the posterior two-thirds they are divided 
into two tracts which may be considered as roots, the one 
internal, the other external. 

The external is most voluminous and also most important. 
It furnishes several fibres which run to various gray ganglia. 
1st. There can be seen a fasciculus which goes to the external 
geniculate body. These bodies are a tolerably voluminous 
mass of gray substance, enclosing ganglionic cells, stellate or 
fusiform, of considerable dimensions, and which are to be 
found well represented in the work of Henle (Fig. 177, p. 
249). 2d. A second fasciculus, situated within the preceding, 
enters the inferior portion of the thalamus about twelve milli- 
metres anterior to the extremity of the pnlvinar. Upon a 
transverse section, such as is represented in the work of Mey- 
nert (Fig. 249, II. R.), the fasciculus in question is situated 
between the external geniculate body and the foot of the 
peduncle. The existence of this fasciculus, affirmed by 
Gratiolet, is also very explicitly recognized by Meynert, 
Henle, and Huguenin. 3d. A third fasciculus which, accord- 
ing to Gratiolet, should be the most apparent and best known 
of the roots of the optic nerves, winds around the external 
geniculate bodies and enters the anterior tuberculum quadri- 
geminus of the corresponding side.^ The description which 
Gratiolet has given of this, confirmed also by Vulpian and 
Huguenin,^ is perfectly exact as concerns the most of mam- 



' Gratiolet, loc. cit., p. 180. 

'Huguenin, Westphall's Arch., V. Bd., ist Heft, 2d Heft, 1875. 



I08 DISEASES OF THE BRAIN. 

mifera." It does not hold true in the same degree for the 
monkey; and in man, though the fasciculus exists, it can be 
anatomically demonstrated only by great care.^ 

It is thus seen that the external roots of the optic nerves 
take their origin in three ganglia of gray substance, to wit : 
1st, the thalami optici ; 2d, the external geniculate bodies; 
3d, the anterior tubercula quadrigemina (nates). Such cer- 
tainly are the principal sources of the optic nerves in man, 
and with a great number of animals they are probably the 
only ones ; at least this seems to be established by the inter- 
esting experiments of Gudden,^ consisting of the extirpation 
of the eyeballs of very young rabbits. In the animals thus 
operated upon, when killed some months thereafter, it was 
observed that consecutive atrophy had ensued in the central 
parts upon the anterior tubercula quadrigemina (nates), the 
thalami optici, and the external geniculate bodies ; on the 
other hand, the posterior tubercula quadrigemina (testes) and 
the internal geniculate bodies did not participate in the atrophy. 

The internal roots, though less important than the external, 
should not be neglected, especially when relating to man. 
You know that they are connected with the internal geniculate 
bodies. These internal geniculate bodies contain only rudi- 
mentary nerve-cells (Henle), and consequently cannot be 
considered as a centre in the same sense as can the external 
geniculate bodies. The nerve-fasciculi of the internal root, it 
may be cither after traversing the geniculate bodies, or by a 
direct course, proceed to a final termination at the anterior 
tubercula quadrigemina (nates). 

Quite recently Huguenin {Arch, fiir Psychiatric, 1875, V. 
Bd., Fasc. 2, p. 344) has maintained that the internal roots of 



^ For brains of the rabbit and dog, see plate, Gudden's work (Arch, of Ophthal., 
XX., 1875) > ^^^ brain of cat, the plates of Forel {Beitrage ztir Kenntniss der 
Thalamus Opticus). Sitzbericht. der k. Akad., LXVI. BJ., 1872, T. II., 
Fig. 10. 

* A fourtli fasciculus, situated outside of the one which stops in the external genic- 
ulate body, is spread upon the thalamus and takes part in forming the Stratum 
zonale. Previously indicated by Arnold and Gratiolet, this fasciculus is described 
and represented also by Meynert, p. 436. 

= Gudden,— Arch, liir Ophthalmol., XX. 



CEREBRAL PORTION OF THE OPTIC NERVES. IO9 

the optic nerves, in man at least, are in anatomical rapport 
with the posterior tubercula quadrigemina, either directly 
or by the intermediation of the internal geniculate bodies. 
According to that, the posterior tubercula quadrigemina 
could not, in man, be excluded, as it seems to be in animals, 
from the apparatus of the optic nerves. This is not in con- 
tradiction with the teaching of certain facts concerning gray 
tabetic induration of the optic nerves. Quite recently, in an 
ataxied woman — blind for fifteen years — gray induration of 
the optic nerves could be followed beyond the chiasma along 
the optic bands quite to the geniculate bodies. The tuber- 
cula quadrigemina, the anterior (nates), as well as the pos- 
terior (testes), had very nearly retained the white color of the 
normal state, but they both were manifestly reduced in size 
(case of Magdaliat^). I have observed several cases, all sim- 
ilar to the preceding. 

We must now examine how the various masses of gray 
substance which have been enumerated are brought into 
relation with the gray cortex of the encephalon. The con- 
nection is established, as I have shown, by a system of fibres 
which constitute the most posterior portion of the radiations 
of the thalami optici (cortico-optic diverging fasciculi), and 
which are sometimes called the optic radiations of Gratiolet. 
You can follow these somewhat complex anatomical details 
in the following plate, which I borrow from the work of Mey- 
nert, and which represents the brain of a monkey {Cercocebiis 
cinomolgus) (Fig. 33), 

It can there be seen how the fasciculi of fibres, or radiations, 
leaving the external geniculate bodies, the internal geniculate 
bodies, the pulvinar, and the anterior tubercula quadrigem- 
ina (these last by the intermediation of the anterior con- 
junctive arms), go by a recurrent way to associate with a 
medullary fasciculus which is only a collection of the direct 
peduncular centripetal fibres that we have already described 
(Lectures VIII. and IX., Fig. 26), and upon which the com- 
mon sensibility of the opposite side of the body depends. 

' The anterior and posterior conjunctive arms were remarkably atrophied ; they 
had a heavy white color, a little tinted with yellow. 



no 



DISEASES OF THE BRAIN. 



With that collection of fibres are doubtless mingled other 
fibres coming from the olfactive tract by way of the anterior 
commissure, the extremities of which, according to the de- 
scriptions of Burdach and Gratiolet, are directed posteriorly 

Sonlal extrermly,. 



Entrance of 
fiss.of Sylviu 



Medullanr fasiciilL 

ging to tuneix quadr 

post.&cmt.,to corp./ 

Fenicul.&foot cf /. 

'eras cerebri. 




Segments' of 
x^entic. nucleus. 



Corpus callosum. 

Queue of caudated 
"nucleus. 

Ant. horn o£ 
iat. ventricle. 

/#-5epiuin lucid . 

g-Crus cerebri, (foot.) 
TAnt .commissuFe. 

iddle ventricle. 



idl: 



e commissure. 



:;,TMiddle ventricle. 

Optic thalarnus_ 
~ant.to coip. genie. 

rCorptis callosuxn. 

rCprpora guadrontern. 
,.ij-A<^ued.uct. 

Corpora quadr. extenit 

^^ Corpora quadrigemirLa 

] ^y^'^'Hom of Amiaoix. 

^Post.hom.ofLatVent. 
Dplic thalamus, 

^Head. of caudated nucleus. 

' Occipital region. 

Fig. 33. — Antero-posterior horizontal section of the left hemisphere of a monkey's 
brain (Cercoceius cinomol^^us). — {Meynert, Strieker's Handbook.) 

into the substance of the occipital and sphenoidal lobes. 
Clinical facts lead to the belief that there also are mingled 
decussating nerve-fibres connected with the auditory and 
gustatory nerves. If that arrangement, now altogether hy- 
pothetical, should come to be anatomically verified, it can 



CEREBRAL PORTION OF THE OPTIC NERVES. Ill 

be understood how crossed obscuration of the smell, taste, 
and hearing should, in the same manner as amblyopia, be an 
ordinary symptom of cerebral hemiancBsthcsia} 

The encephalic region to which I have drawn your atten- 
tion, and which responds to the most posterior part of the 
foot of the radiating fibres {couronne rayonnante), may be 
considered, then, as a highway where, in the depths of the en- 
cephalon, are encountered, within a very narrow space, all the 
sensitive and sensorial lines of travel. This is a highway ; 
it is not a centre. The cerebral centre, properly speaking, 
should be sought in the prolongations of the medullary fibres, 
in the gray cortex of the occipital and sphenoidal lobes. 

We shall return to this point in connection with localiza- 
tions in the cortical system. 

III. You might have observed in the preceding anatomical 
expose that the tubercula quadrigemina seem to furnish the 
only point where the fasciculi of the optic nerves, after their 
decussation in the chiasma, again approach each other upon 
the median line. This is the point where that supplementary 
decussation is effected, which, according to my hypothesis, 
would reduce the optic nerve to the same footing as other 
nerves. That is a question which at present seems difficult 
to resolve by exclusively anatomical means. Upon the 
median line, between the tubercula quadrigemina, numerous 
decussations of fibres are without doubt anatomically demon- 
strated. But it cannot be decided whether these decussated 
fibres are really in connection with the optic nerves, and es- 
pecially whether they are the prolongations of optic fibres 
non-decussating in the chiasma. Experimentation, and above 
all pathological anatomy, should certainly have the first place 
in the solution of this question. The experiments of Flou- 
rens have already shown that with mammifera and with birds, 
the ablation of the optic tubercles produce amblyopia or 
crossed amaurosis. But this is with animals in which the 

' Accoi'ding to the theory, cerebral hemianesthesias should be distinguished 
fron* those dependent upon a legion of the protuberance or the cerebral peduncles 
(crus cerebri) by non-participation in the last case of vision or smell. 



112 DISEASES OF THE BRAIN. 

ocular axes are directed externally and in which the decus- 
sation in the chiasma is doubtless complete. 

With man the elements for the solution of the problem are 
as yet defective. With him lesions of the tubercula quadri- 
gemina are not rare, but they ordinarily are bilateral, and 
consequently producing bilateral blindness, they can prove 
nothing. In fact, it is still a question whether lesions of the 
anterior tubercula quadrigemina will, like a lesion of the optic 
bands, produce lateral hemiopia, or if, on the contrary, they 
will produce crossed amblyopia, as would be in keeping with 
my hypothesis. In favor of my hypothesis, I can as yet cite 
but one case, reported by Dr. Bastian, and in which a unilat- 
eral lesion of the anterior tubercula quadrigemina had pro- 
duced crossed amblyopia. 

But that fact is at present the only one, and besides it is 
related with too little detail to be received as decisive.^ 

IV. It remains to ascertain if crossed amblyopia is the 
only kind of functional trouble of the vision which can be 
produced by a lesion of the brain proper, or if, on the con- 
trary, hemiopia may not also follow as a consequence of cer- 
tain pathological localizations in the hemisphere. That is a 
point which, I think, no one is at pr-esent competent to de- 
cide. I incline, however, in the absence of contradictory 
autopsies, to believe that in most instances of hemiopia 
which have been ascribed to a lesion of the brain, the lesion 
has either not occupied the deep regions of the hemisphere, 
or that it has extended to the basilar portions in such manner 
as to involve more or less directly one or the other of the 
optic bands. 

To show that deep lesions of the brain produce hemiopia — 
lateral hemiopia — cases are specially cited where the visual 
disturbance is suddenly developed upon an apoplectic stroke, 
and where, at the same time, the limbs of one side are affected 
with motor hemiplegia, and sometimes also with anaesthesia. 
Nothing is better established in clinic than facts of this kind, 

' H. C. Bastian, The Lancet, 1874, 25th July. 



CEREBRAL PORTION OF THE OPTIC NERVES. II 3 

of which Schocn, quite recently, in an interesting work, has 
cited several examples.^ But the conduction of the autopsies 
have to the present been faulty, and it may be queried if the 
lesion found in these cases occupied really the deep brain, or, 
on the contrary, the base of the encephalon. It seems estab- 
lished, you have not forgotten, that destruction or compres- 
sion of one of the optic bands produces lateral hemiopia ; and, 
on the other hand, the anatomical relation which exists be- 
tween the bands and certain parts of the isthmus, such, 
among others, as the crura cerebri, is well known. Such 
being the case, it could not be otherwise than that a lesion 
properly localized, as, for example, in a crus cerebri, might 
result in producing at the same time lateral hemiopia and 
motor hemiplegia, and perhaps also hemianaesthesia. Hem- 
orrhage, suddenly developed in the substance of the pos- 
terior part of the thalami optici, might, as can be understood, 
be followed with the same effect. It is evident that these 
diverse combinations are only phenomena of propinquity. 

In any case, it should be known that among instances 
which have been reported of lateral hemiopia of supposed 
intracerebral origin, there are a certain number which in some 
respects do not conform to the interpretations that I have 
proposed. Such, among others, are those where right lateral 
hemiopia develops itself in concert with aphasia, and some- 
times also with various modifications of the sensibility or 
motion of the limbs of the right side of the body.^ 

These facts do not constitute a homogeneous group ; the 
first category includes a form peculiar to migraine^ that is, 
symptoms essentially transitory, returning by accesses, and 
above all marked by scintillations, vertigo, more or less 
marked lateral hemiopia, and sometimes also with a certain 

' Arch, der Heilkunde, p. 19, 1875. 

"Various cases of this kind have recently been related by Bernhardt (Berliner 
klin. Wochen., 32, 1872, and Centralblatt, 1S72, 39), and by Schoen (loc. cit.). 
See also H. Jackson, A Case of Hemiopia with Hemianesthesia and Hemiplegia, 
in the Lancet, Aug. 29, 1874, p. 306. 

^ See respecting this form of migraine the works of Tissot, Labarraque, Piorry, 
and Latham (on Nervous Sick Headache, Cambridge, 1S73), and above all the re- 
cent work of Ed. Liveing (on Megrim, etc., London, 1873). 



114 DISEASES OF THE BRAIN. 

degree of aphasia and numbness in the face and Hmbs of the 
right side. Headache, nausea, and vomiting usually end the 
attack. It is clear that these cases cannot be ascribed to a 
durable, material alteration. It is not thus with the cases of 
the second category, where the concurrence of aphasia, hemi- 
plegia, and hemiopia remain permanent.^ 

At present I do not see how these various cases, revealed 
by clinic, can be anatomically explained upon the hypothesis 
of a single lesion. I can only call attention to the difficulties, 
the solution of which is reserved to the future. 



' It can be understood that a voluminous tumor might produce all the results 
noted in both categories, and it has happened in a case recently published by 
Hirschberg in the Archives of Virchow (Virchovv's Arch., T. 65, i Heft, p. n6). 
This patient had, besides very characteristic right lateral hemiopia, aphasia, and 
hemiplegia of the right limbs. Upon autopsy there was found in the substance of 
the left frontal lobe, a tumor the size of an apple, of the kind called vascular 
glioma. The optic tract of the left side was very flattened. The views enter- 
tained in the present chapter find a confirmation m that fact, since the hemiopia 
there noted may belong to compression of the optic tract. 



TWELFTH LECTURE. 

SECONDARY DEGENERATION. 

Summary : — Anterior or Ijenticiilo-Striatecl Region of tlie Central Masses 
(Anterior Two-tUircls of Internal Capsule, tlie Caudatccl and 
Iienticular Ganglia). — Influence of Lesions in tlicse Regions upon 
tlie Production of Motor Hemiplegia. — Experimental Facts. — Accord 
between tliese and the Facts of Human Pathology. — Difference 
het^v'cen the Lesions of the Caudated Ganglion and those of the 
Anterior Part of the Internal Capsule. — Secondary Degenerations, 
or Descending Scleroses. — Lesions ■which Produce them ; Impor- 
tance of the Locality and Extent of these Lesions. — Cliaracteristics 
of Descending Scleroses; Extent; Appearance of the Lesion upon the 
Crus Cerebri, the Protuberance, the Anterior Pyramid, and the Lat- 
eral Fasciculus of the Spinal Cord. — Analogies and Differences be- 
tween Lateral Sclerosis from Cerebral Cause, and Primitive Fascicu- 
lated Sclerosis of the Lateral Fasciculi. — Symptoms Belonging to Sec- 
ondary Sclerosis; Motor Impotency, Permanent Contractions. — Mus- 
cular Atrophy Produced by Extension of the Lateral Sclerosis to the 
Cornua of the Gray Substance. — Descending Sclerosis Following 
a Lesion of the Cortex. — Demonstration of the Di»"ect Peduncular 
Fibres ; Anatomico-Pathological Facts. — The Locations of Coi-tical 
Lesions which Proiluce Secondary Degenerations Correspond to 
the Locations of Centres called Psycho.Motor. 

Gentlemen : 

We must again turn to the anierzor regions of tJie central 
masses, for the purpose of studying more carefully the ana- 
tomical and pathologico-physiological effects of lesions occur- 
ring in that locality. 

That region, which may be called the lenticulo-striated , in 
contradistinction to the posterior or lenticulo-optic region, 
embraces, you remember, ist, the anterior two-thirds of the 
white tract called the internal capsule ; 2d, internally from 
this, the large extremity or head of the caudated ganglion ; 
3d, outside, by the side of the island of Reil, the anterior two- 
thirds nearly of the lenticulatc ganglion. 



ii6 



DISEASES OF THE BRAIN. 



Observation, and that many times repeated, demonstrates 
as I have already remarked in the course of these lectures 
Lectures VIII. and IX., pp. 70 and 71), that common motor 
hemiplegia, unaccompanied by derangement of sensibility, is 
the almost inevitable consequence of even the smallest lesions 
occurring in the various parts which I have enumerated, 
provided always that the lesions in question produce the de- 



li xl'.capsula 



Corpus 
callosum. 

Ependyniatic 
membrane 



Opiie 
iliabmus. 




of. T? pit 



fCentenif-Qliisofkning 

Fig. 34. — An old softening of the middle portion of the caudated ganglion and the 
internal capsule. [Right side. ) 

struction or the sudden compression of the nerve-elements of 
the affected area, instead of merely a slowly effected dis- 
placement, as is often seen in the case of tumors. 

I called attention to an important distinction which should 
be established. This is, that lesions, even extensive and 
deep, which remain limited to the gray ganglia (caudated 
and lenticular ganglia), produce, as a general rule, symptoms 
relatively slight and transient, while lesions comparatively 



SECONDARY DEGENERATION. I 17 

slight, which involve the white tract (internal capsule), give 
rise to a motor hemiplegia, not only very decided, but also 
of long duration and often incurable (Fig. 34). 

Let us try and ascertain the reason of these differences. 
First, concerning the intensity of the paralytic symptoms in 
cases of lesions of the internal capsule compared to that mild 
degree in cases of lesions limited to the gray ganglia ; then 
we will examine the transitory character of hemiplegia in the 
last kind of cases as contrasted with the permanence of the 
same symptom which almost invariably results from lesions 
of the internal capsule. 

I. Concerning the first point, I will remind you again of 
the anatomical construction of the internal capsule. That 
tract embraces : 1st. The direct peduncular fibres — that is, 
those originating beneath the gray cortex, and which enter 
the inferior portion of the crura cerebri without having entered 
into relation with the lenticular or caudated gray ganglia. 
2d. The indirect peduncular fibres^ which, on the contrary, 
originate in the lenticular or caudated ganglia, and have no 
connection with the gray cortex. For the moment we will 
leave unnoticed those fasciculi of fibres which extend from the 
cortical substance to the gray ganglia of the central mass. 

We will suppose that the various peduncular fibres, direct 
and indirect, are centrifugal, and that they transmit to the 
periphery the motor influence developed, it may be, in the 
gray cortex of the brain, or in the lenticular and caudated 
gray ganglia. 

With this hypothesis it is easy to comprehend that a small 
lesion of the internal capsule, especially near its inferior part, 
in the vicinity of the foot of the cerebral peduncle, where all 
the fibres are reassembled in a narrow space, would, at one 
blow, suppress the influence of the gray cortex and that of 
the two gray ganglia ; while, on the contrary, a lesion limited 
to the lenticular ganglion would leave free the action of the 
caudated ganglion and that of the gray cortex. The effects 
of various combinations of this sort which might happen can 
easily be imagined ; lesion of the caudated ganglion, of cer- 



Il8 DISEASES OF THE BRAIN. 

tain regions of the gray cortex, of the two gray ganglia, with 
or without the participation of the peduncular fibres of the 
internal capsule, etc. 

I attach no more importance to this theoretical view than 
is permissible. It adapts itself well to the facts obtained by 
clinical observation upon man, and I will add also that it is 
in no part contradicted (you may judge for yourselves) by 
experiments made with animals. 

For a long time it has been known ^ that with the majority 
of animals motor disturbances produced by the methodic de- 
struction of various parts of the encephalon, particularly of 
the brain, differ considerably in a general way from similar 
pathological lesions of corresponding parts in man. 

In the interpretation of these experimental facts, and in 
their application to human pathology, there should be taken 
into account, among other things, the greater or less inferior- 
ity of the species of animals and the more or less advanced 
age. Thus, the entire ablation of a cerebral hemisphere of a 
pigeon (and still more marked, of course, with a reptile) 
would produce no trouble which could be compared to hemi- 
plegia. It is nearly the same with the rabbit. A feebleness 
slightly noticeable in the limbs of one side of the body is the 
only consequence of such a lesion in the rabbit. Standing 
and jumping are still possible, even though the entire brain 
has been destro}-ed, provided always that the protuberance 
remains intact.' With the dog, the results become notably 
different. From the last experiments made in the laboratory 
of Vulpian, by Carville and Duret, the results of methodic 
ablation of the various parts of the dog's brain greatly resem- 
ble those observed in cases of corresponding lesions of the 
cerebral hemisphere in man. 

If the experiments were made upon the monkey, it is prob- 
able that the resemblance would be still more manifest and 
complete. 

Here is a brief expose of the principal results obtained by 



' See upon this subject Longet. — Traite de physiologic, t. III., p. 431, and 
Vulpian. — Le9ons sur la physiologic generalc, etc., p. 676. 
- Vulpian, Longet. 



SECONDARY DEGENERATION, 



119 



the experiments of Carville and Duret : ist. In the dog, ab- 
lation of the gray substance of the central cortex of those 
regions called motor centres produced a temporary weakness 
{paresis) of the limbs upon 



the opposite side. 2d. The 
extirpation of the caudated 
ganglion produced an anal- 
ogous but more marked 
paresis. Nothing can at 
present be said of the len- 
ticular ganglion, the ablation 
of which, owing to its topo- 
graphical position, could not 
be effected ; ^ 3d. If, on the 
contrary, the lesion be made 
upon the inferior part of the 
internal capsule, it produces 
in both fore and hind limbs Intcapsule,' . 



Xenlicular iTQcletis'^ 
jg Section of ant. portiori) i 
of internal capsule} I 
Cauda tedniidei 
•\of corpora 'stfiaia. 




^ lint, capsule, 



c A.\^ -i. -J .- Chiasma of optic nerves. 

of the opposite side, not ^ . 

. . Fig. 35. — Transverse section of a dog 

only a simple paresis, but brain, five millimetres interior to the opti*^ 
, 1 1 1 .L 1 chiasma. ( Operation of Veyssiire. ) 

a well-marked motor paraly- 
sis which resembles the hemiplegia in man resulting from le- 
sions of the same parts (Fig. 35). Held suspended by the 
skin of the back, the animal thus operated on could still stand 
on the sound limbs, but the affected ones hung flaccid, inert ^ 
and no longer capable of any movement except that which was 
purely reflex. 

In short, you see from these interesting researches, which 
are worthy of multiplication, that the contradiction long since 
noticed between animals and man, relative to the influence of 
various parts of the hemisphere of the brain upon movement of 
the opposite limbs — that contradiction, I say, seems no longer 
to exist when the specimen for the comparison is relatively high 
in the animal scale. (Fig. 36.) 

Perhaps it is not here out of the way to recall that even in 

' In this rc!;pect it is difficult to utilize the experiments of Nothnagel with caus- 
tic injections. These injections must almost necessarily produce phenomena of 
excitation, which assuredly introduce a complication. 



120 



DISEASES OF THE BRAIN. 



the dog — the result of experiments by both Carville and 
Duret and Veyssiere — lesions of the posterior part of the inter- 
nal capsule produced crossed hemianaesthesia the same as 
with man. 

II. I think the previous considerations may render plain 
the reason why hemiplegias resulting from destructive lesions 



Cavidat^d nuclei 

In t . caps ule , -post .por b'on . 




HornsV ---'"■ 
of-Ammon.. 



S ect of post .part 
of int/l. capsule 



Fig. 36. — Transverse section of a dog's brain on a plane with the tubercula mamniil- 
laria — {Carville and Duret.) 

confined to the substance of the gray ganglia are as a rule 
temporary, while those resulting from lesions in the substance 
of the internal capsule are, on the contrary, of longer dura- 
tion, and often even absolutely incurable. 

Through the hypothesis proposed, it can easily be under- 
stood how the lenticular and caudated ganglia and the regions 
called the motor centres in the gray cortex of the hemispheres 
could mutually supplement each other in their functions, so 
long as the conducting fasciculi which form the capsule have 
preserved their integrity, and c-ould continue to maintain the 
relations of any one of the gray centres in question with the 
peripheric parts ; whereas this could not take place if the 
continuity of these fasciculi had been decidedly interrupted. 

I will add that in all probability this supplementing may be 
established not only between the various gray ganglia, but 
also between the various parts of the same ganglion. It is 



SECONDARY DEGENERATION. 121 

demonstrated, at least as concerns the caudated ganglion of 
the corpus striatum, that partially destructive lesions affecting 
the most diverse regions of the ganglion are uniformly ex- 
pressed by a more or less marked and transitory, but total 
hemiplegia ; that is, affecting at the same time both the face 
and the limbs. In this respect there can be distinguished no 
difference between the head, the tail, or the middle part of 
the caudated ganglion. It would thus seem that H.Jackson 
was correct in remarking that each parcel of the striated body 
represented in miniature the entire body. Moreover, experi- 
mentation gives results in conformity with those furnished by 
clinical observation, in showing that partial excitation of the 
caudated ganglion, however effected, always produces move- 
ments of the entire opposite side of the body, and never dis- 
associated movements ; localized, for example, in one limb, or 
in a portion of a limb.' 

In case of a destructive lesion of the internal capsule, a 
slow regeneration of the nerve-elements may, on the contrary, 
permit the gradual re-establishment of the functions. Now, 
that labor of restitution, if it is really sometimes accomplished, 
most certainly is not always so ; it occurs only as an excep- 
tion. It is placed beyond doubt, indeed, by very numerous 
observations, that those lesions which to a certain extent de- 
stroy the motor fibres of the internal capsule, have, as an 
almost necessary consequence, the production of a fascicular 
lesion which, commencing immediately below the site of the 
lesion, can be traced in the corresponding side to the foot of 
the peduncle, along the protuberance, and the anterior pyr- 
amid to the level of the bulbular decussation, and beneath 
this into the spinal cord, on the side opposite to that of the 
lesion, through the entire length of the lateral fasciculus down 
to the lumbar enlargement. 

III. I think some explanations concerning the anatomy 
and pathological physiology of secondary degenerative or de- 
scending scleroses, as they still may be called, will not here 

' Experiences of Ferrier, Carville and Duret. 



122 DISEASES OF THE BRAIN. 

be amiss. They are incontestably one of the principal causes 
of the persistence of motor impotency in the cases under con- 
sideration. In my opinion, we must also join to them the 
major part oi pcrjuanent contractions, called late contractions 
{tardive^ which in these cases sooner or later take possession 
of the paralyzed limbs, and in a general way play a predom- 
inant r61e in the prognosis of cerebral hemorrhage. 

1st. Let us first pause in face of a fact which really rules 
the question : cerebral lesions {en foyer), considered as re- 
spects their location, are not all equally able to produce con- 
secutive sclerosis. 

Thus, among these lesions, some are never followed by 
descending sclerosis, while others almost surely are. To this 
last kind belong destructive lesions, however slight, which, 
according to the important observation of L. Tiirck, involve 
the fasciculi of the internal capsule in their course between the 
lenticular and caudated ganglia, that is, along the anterior 
two-thirds of the capsule. On the contrary, those lesions con- 
fined to the substance of the gray cerebral masses, namely, 
the lenticulated and caudated ganglia and the thalami optici, 
produce no consecutive sclerosis. 

That remarkable fact was thoroughly brought to light by 
L. Tiirck^ in 1851. Vulpian and I have both recognized 
its entire exactitude in the researches which we have made 
together at Salpetriere from 1861 to 1866.^^ The important 
works of Bouchard have equally confirmed it.** There are also 
a certain number of other facts, furnished by L. Tiirck, not less 
interesting, and of which the following is the gist : 

' We are indebted, as is known, to Dr. Todd for having established a distinc- 
tion between early and late {precoce et tardive) contraction in the limbs of an 
apoplectic. The first appears at the commencement and is nearly always transitory ; 
the other does not appear before the fourteenth to the thirtieth day after the attack, 
is situated always in the limbs of the side opposite to the lesion, and in the 
majority of cases is permanent. 

* L. Tiirck. — Ueber secundare Erkrankung einzelner RUckenmarkstrange und 
ihrer Forsetzungen zum Gehirne. Sitzungsber. der mathnatur. Classe d. K. Ak., 
1851. Idem., XI. Bd., 1853. 

^ A. Vulpian. — Physiologic du systeme nerveux, Paris, 1S66. 

■• Ch. Bouchard.— Des degenerations secondaires de la moUe epiniere. In iKrch. 
gen. de medecine, 1866. 



SECONDARY DEGENERATION. 



123 



2d. Lesions situated outside of the central masses, in the 
centrum ovale of Vieussens, produce descending sclerosis, 
provided they are not too far removed from the foot of the 
radiating fibres {couronne rayonitante). 

3d. .Lesions of the gray cortical substance of the hemi- 
spheres, when they are very superficial, such, for example, as 
those which habitually accompany meningitis, do not produce 
descending sclerosis. 




Fig. 37. — Cortical ischcemic softening without involving the central masses. 



Center q^ 
^oftenirig". 



4th. On the contrary, cortical lesions which are both 
extended and profound, that is, involving both the gray sub- 
stance and the subjacent medullary substance, as seen in 
cases of ischaemic softening resulting, for example, from the 
obliteration of a voluminous branch of the Sylvian artery 
(see Fig. 37) — these lesions, I say, even ivhen there is tio par- 
ticipation of the central masses, produce ifi certain cases con- 
secutive sclerosis as marked as that which depends upon a 
lesion of the anterior region of the internal capsule. 

Among these conditions there is one especially relating to 
the location of cortical lesions, which should be made partic- 
ularly clear. We have observed that superficial softenings 
(yellow patches) occupying either the occipital lobe, the pos- 



124 



DISEASES OF THE BRAIN. 



terior parts of the temporal or sphenoidal lobe, or the ante- 
rior regions of the frontal lobe, are not succeeded by consec- 
utive fascicular sclerosis, while on the other hand these scle- 
roses, as a rule, follow lesions of the two ascending convolu- 
tions (ascending parietal and ascending frontal), and the con- 
tiguous parts of the parietal and frontal lobes (Fig. 38). Fur- 
ther on I will return more especially to this point, which I 
now merely mention. 




Fig. 38. — Human brain, left side ; destruction of the ascending parietal convolu- 
tion and a great part of the ascending frontal convolution. 

5th. In brief, the locality and extent of the lesion seem 
here to be the two fundamental conditions ; the nature of the 
lesion seems to have no marked influence. The required 
locality and extent being given, descending sclerosis should 
follow, provided the lesion is a destructive one, that is, one 
capable of interrupting the course of the medullar)"- fibres. 
Centres of hemorrhage or softening, and simple or syphilitic 
encephalitis, have in this respect much the same rank. It is 
not the same with certain tumors which, through a long period 
of evolution, only crowd back or to one side the medul- 
lary elements without interrupting their continuity. This is 
the reason why they may exist, even in the regions above 
specified, unaccompanied by consecutive fascicular scle- 
rosis. 



SFXONDARY DEGENERATION. 1 25 

IV. As for the anatomy of fascicular sclerosis, I refer for 
details to the important vieinoire published by Bouchard. I 
will only remind you of some facts to which our present stud- 
ies giv^e a particular interest. 

1st. I will commence by recalling that sclerosis following a 
lesion icn foyer) in the cerebral hemispheres always occupies 
one-half of the lateral fasciculi. It is more or less marked and 
more or less extensive according to the size of the fasciculus ; 
but always extends down to the inferior end of the lumbar en- 
largement, never stops by the way. They are always descend- 
ing, in the sense that, taking origin on a level with the point 
of lesion, they never extend except below that point ; they 
are never found above it, towards the gray cortex. The 
atrophy of one or several of the convolutions, or even of the 
entire hemisphere, such as is seen when a central lesion {en 
foyer) is developed in very young subjects, is not necessarily 
the result of a sclerosis. That arises from an arrest of de- 
velopment which may be compared to atrophy, which, under 
like circumstances, is to be seen in the limbs upon the side 
of the body affected by hemiplegia (infantile spasmodic hemi- 
plegia). 

2d. Microscopic examination alone, in cases which have 
existed for some time and are rather marked, can recognize 
some of the most prominent characters of the alteration. Let 
us suppose a yellow patch, interrupting in the left hemisphere 
the course of the fibres of the internal capsule in its middle 
third. In such a case the foot of the crus cerebri of the left 
side will appear flatter and narrower than that of the opposite 
side. There will also be seen a grayish band situated upon 
the middle part of the peduncle,^ which upon an antero-pos- 
terior section does not extend beyond the gray layer of Soem- 
mering. The gray color disappears at the level of the protu- 
berance ; it is found again below, in the bulb, where it occu- 
pies the entire extent of the anterior pyramid on the side 
corresponding to the cerebral lesion ; the affected pyramid is 

' The situation occupied by that band varies according to the location of the 
central lesion ; it is nearer the internal border of the foot of the peduncle in pro- 
portion as the lesion of the capsule is situated anteriorly. 



126 DISEASES OF THE BRAIN. 

narrowed and flattened ; lower down, the teeth of the bulbu- 
lar decussation show more distinctly than in the normal con- 
dition by reason of the contrast which exists between the 
sound and diseased sides. Below the decussation it is in the 
opposite side of the spinal cord (opposite to the affected 
hemisphere), in the lateral fasciculus, that the sclerosis should 
be sought for ; the alteration is in the form of a triangular 
space, of gray color, situated immediately external and ante- 
rior to the corresponding posterior gray cornu, the area of 
which lessens in proportion as the sections are made lower 
down on the cord. 

3d. Microscopic studies, made upon sections properly hard- 
ened and prepared, greatly contribute to our knowledge. 
In the first place, they furnish the means for locating more 
exactly the topography of the lesion, and to make known, in 
the spinal cord, for example, the precise limitation of the area 
in the lateral fasciculus. The other white fasciculi and the gray 
cornua remain entirely unchanged. It is to be noticed, at the 
same time, that the roots of the nerves, anterior and poste- 
rior, as well as the meninges, exhibit no trace of alteration. 

Lastly, the microscope makes known also the nature of the 
morbid process, and furnishes proof of a gray induration — a 
sclerosis which differs in no essential particular from that 
observed in cases of primitive fascicular sclerosis.^ 

4th. Here is the place to call attention to the analogies 
which exist in an anatomico-pathological point of view be- 
tween consecutive fascicular sclerosis, of cerebral origin, and 
those primitive and symmetrical fascicular scleroses of the lat- 
eral fasciculi which I last year described in connection with 
spinal muscular atrophy {amyotrophies spinales). 

These analogies are considerable, since the same alteration 
(gray induration) is in both cases located in the same tissue. 
But there arc also variations worthy of notice ; thus, in prim- 
itive sclerosis the fascicular lesions are necessarily double, that 

' Those cases where the extension of the lesion exceeds its habitual limits, the 
invasion, for example, of the anterior gray cornua, which will be considered farther 
on, are certainly among the most decisive arguments which can be employed to 
establish the irritative nature of the morbid process. 



SECONDARY DEGENERATION. 



127 



is, they occupy the lateral fascicuH of both sides simulta- 
neously, instead of one side only, as is always the case in con- 
secutive sclerosis, when the lesion from which it arises is uni- 
lateral. I will also add that it is very much less extended 
transversely, and there is reason to believe, therefore, that 
beyond the cerebro-spinal or pyramidal fibres, which are the 
only ones affected in consecutive sclerosis, primitive sclero- 




FiG. 40. 



Fig. 39. 



Fig. 39. — Transverse section of the spinal cord in a case of consecutive lateral fas- 
cicular sclerosis ; from softening of the optico-striated bodies and the internal capsule. 
(Cervical region.) 

Fig. 40. — Transverse section of the spinal cord in a case of consecutive lateral 
fascicular sclerosis. (Dorsal region.) 

sis invades also the spinal fibres of the lateral fasciculus (com- 
pare Figs. 39, 40, and 41, and Figs. 42, 43, and 44). 




Fig. 41 



Fig. 42. 



Fig. 41. — Transverse section of the spinal cord in a case of consecutive lateral 
fascicular sclerosis. (Lumbar region.) 

Fig. 42. — Transverse section of the spinal cord in a case of primitive lateral 
fascicular sclerosis. (Middle portion of cervical enlargement.) 

Finally, primitive sclerosis has a great tendency to extend 
to the neighboring spinal regions, to the white fasciculi, and 



128 DISEASES OF THE BRAIN. 

especially the anterior cornua of the gray substance, which 
is not the rule in the consecutive form.^ 




Fig. 43- 




Fig. 44. 



Fig. 43. — Transverse section of the spinal cord in a case of primitive lateral fas- 
cicular sclerosis. (Middle of dorsal region.) 

Fig. 44, — Transverse section of the spinal cord in a case of primitive lateral 
fascicular sclerosis. (Middle of lumbar enlargement.) 

' Here are some more precise details relative to the anatomical differences 
existing between consecutive lateral sclerosis and primitive lateral sclerosis, amyo- 
trophic. They are examinations made upon hardened transverse sections, where, 
even in the bulb, secondary sclerosis has involved nearly all the fibres of the ante- 
rior pyramid, and in the spinal cord the lesion occupies only a comparatively nar- 
row space in the lateral fasciculus. Upon a transverse section made at the cervi- 
cal enlargement, the lesion is seen as a triangle with very clearly defined borders, 
the apex of which is directed inward toward the angle which separates the ante- 
rior from the posterior gray cornua, the base a little rounded, does not extend to 
the circumference of the cord, neither does it involve the antero-external border of 
the posterior cornu (Fig. 39). In the dorsal region the sclerotic portion pro- 
gressively dimmishes in diameter and tends to resume an oval form (Fig. 40). 
Finally, in the lumbar enlargement (Fig. 41), it resumes as in the cervical region, a 
sort of triangle, but in this locality the base of the triangle is quite superficial, next 
to the pia mater. 

In primitive lateral sclerosis, the sclerotic zone occupies in a general way the 
same region as does consecutive sclerosis, but its area is much greater. Thus, 
anteriorly, the lesion tends to invade the anterior radiating zones, and internally 
it extends so as to come in contact with the nerve-fibres (perhaps sensitive) which 
constitute the profound part of the lateral fasciculi (see Figs. 42, 43, 44). It must 
be added that here the borders of the lesions become ill-defined. In some cases 
they seem to be confounded with the gray substance. It is known that the gray 
substance is regularly invaded by sclerotic alterations in cases of lateral amyotro- 
phic sclerosis, whereas it is very exceptional in consecutive sclerosis from cerebral 
cause. 

From the preceding considerations there is reason to think tliat consecutive 
sclerosis affects only one part of the nerve-fibres which compose the lateral fas- 
ciculi, namely, the cerebro-spinal fibres ; whereas, in primitive sclerosis, it invades 



SECONDARY DEGEXERATIOX. I 29 

There is, however, a chapter of exceptions which in tliis 
connection is particularly interesting. 

ly. The facts gathered in the course of the preceding 
expose enable us to justify the proposition with which this 
chapter commenced. We have established in an anatomical 
point of view that there exists a very considerable analogy 
between primitive and consecutive forms of lateral fascicular 
sclerosis. That assimilation can be followed upon the clini- 
cal field. It is known, indeed, that motor loss, contraction of 
the limbs, at first transient, then permanent, with sponta- 
neous or provoked trepidation, etc., provide a symptomatic 
group which reveals during life the existence of primitive 
fascicular spinal sclerosis, that is, independent of any cerebral 
lesion. Now all the essential characters of these symptoms 
are reproduced in sclerosis arising from a lesion in the brain, 
the clinical picture, in fact, of common permanent hemiplegia. 
It may be said, then, that there exists a relation between the 
phenomenon of " permanent contraction " and " lateral sclero- 
sis," the physiological reason of which at present completely 
eludes us, but the reality of which is nevertheless established 
by a great number of observations.^ 

In my opinion, it is not the retraction of the cerebral cica- 
trix, as Todd would hold, nor yet encephalitis supervening 
from proximity to the lesion, as very many authors at present 
maintain, which can explain the apparition of those contrac- 
tions in hemiplegias called tardy {tardive) ; on the contrary, 
it is more reasonable to attribute it to a chronic myelitis in 
the lateral fasciculus resulting from the cerebral lesion. I will 
avoid discussion, and once more refer you to the work already 
cited of Bouchard, in which will be found all the proofs that 
can be adduced in favor of my opinion. 

Consecutive sclerosis resulting from cerebral lesion ac- 



the entire lateral system, including not only the cerebro-spinal and pyramidal 
fibres, but also those fibres which both commence and terminate in the spinal 
cord — \}[\o%t fibres properly called sfittal fibres. 

' Permanent contraction of the limbs, as is seen in other complaints, such as hys- 
teria, may exist without lateral spinal sclerosis; but when that lesion exists, per- 
manent contraction is an habitual symptom. 



I30 DISEASES OF THE BRAIN. 

quires, after a given time, a kind of independent existence, 
automatic ; this is evinced by special symptoms. By reason 
of this autonomy the lesion may happen to extend beyond 
the limits habitually assigned to it in the lateral fasciculus, and 
invade the adjacent parts of the spinal cord, the substance of 
the gray cornua, for example ; in such cases it is comprehen- 
sible that important modifications may occur in the symp- 
tomatic tableau ; thus, the muscles of the paralyzed limbs, 
which in permanent hemiplegia ordinarily preserve their nor- 
mal texture for a long time, and but slowly emaciate, are 
subject, in certain cases, to a degenerative atrophy, more or 
less rapid, at the same time that the rigidity of the contrac- 
tion gives way to renewed flaccidity. In several examples 
of this kind, Pierret and I have demonstrated, in addition to 
the classic lateral sclerosis, a lesion of the anterior gray cornu 
of the same side, including the destruction of the large nerve- 
cells of that region. The invasion of the posterior gray cor- 
nu might in like manner explain the appearance of certain 
partial anaesthesia in common hemiplegia. Lastly, the exten- 
sion of the initiative process, whether along the whole course 
of the lateral fasciculus of the corresponding side, or be it of 
the lateral fasciculus of the opposite side, would doubtless ex- 
plain the fact that, contrary to common observation, the con- 
traction of the lower limb is at some one period considerably 
greater, or sometimes extends to the opposite limb.^ 

V. To the present I have only occupied myself with fas- 
cicular sclerosis arising from lesion of the central cerebral 
masses. I now wish to give a moment to those produced by 
lesions of the cortex. So far as concerns the aft'ection of the 
spine or the bulb, lateral sclerosis, from lesions of the cen- 
tral masses, in no way differs from that following lesions of the 
cortex. The special conditions of development constitute all 
the difference, and this calls for new details. 

You remember how you have been led to admit, on the 
grounds of a very probable hypothesis, the existence of di- 

' In this connection see Bastian — Paralysb from Brain Diseases, etc., p. 141. 
Ixjndon, 1875. 



SECONDARY DEGENERATION. 131 

rect peduncular fibres — that is, those which, after leaving the 
foot of the peduncle, traverse the internal capsule without 
entering the gray ganglia of the central masses, and conse- 
quently do not stop until they reach the gray cortical sub- 
stance ; besides the arguments already employed, some facts 
of experimentation can be cited in favor of the existence of 
such fibres, even with animals of low scale, the rabbit for ex- 
ample. Thus in the experiments already noticed of Gudden,^ 
made upon very young animals, it is seen that eight months 
after the removal of the anterior part of a hemisphere, the 
central masses, thalami optici, and corpora striata being un- 
touched, the internal capsule of the corresponding side atro- 
phies in a remarkable manner. It is clear that such atrophy 
would not occur if the internal capsule, as some anatomists 
hold, were exclusively composed of indirect peduncular fibres ^ 
— that is, of fibres terminating in the substance of the central 
gray ganglia. 

Chance brought to the notice of Carville and Duret^ a 
lesion in a dog which had destroyed all the white substance 
of the frontal portion of a lobe without directly affecting the 
central gray ganglia or the internal capsule. In this case 
there was a very marked atrophy of the foot of the peduncle, 
the protuberance, and of the pyramidal bulb of the side cor- 
responding to the cerebral lesion. 

The reality of these direct peduncular fibres in man seems 
in its turn to be proven by the production of the secondary 
degenerations which, as we have said, are a result of exten- 
sive and deep lesions of the gray cortical substance. 

Do these direct peduncular fibres, after their disappearance 
in the diverging fibres, spread indifferently to all parts of the 
hemisphere, or are they assigned to special departments of 
the gray cortex ? The facts which I have collected towards 
the study of that question plead in favor of the last hypothe- 
sis. These observations, collected for me at the Hospital of 
Saltpetriere during the last fifteen years, relate to cases of 



' Archiv fur Psychiatric, Bd. II., 1870, pL VIII. 
* Archives de physiologic, 1875. 



M2 



DISEASES OF THE DRAIN. 



long-standing ischiemic softening.^ The lesions in these cases 
appeared as yelloio patches of variable size, extending more 
or less deeply into the subjacent white substance and occu- 
pying the most diverse regions of the surface of the hemi- 
spheres. In all the cases it is expressly mentioned that the 
softenings had left the central masses, thalami optici, cau- 
dated and lenticular ganglia, and internal capsule, entirely 
untouched. My observations may be divided into two 
groups. 




Fig. 45. — Human brain, left side ; destruction of the ascending parietal convolu- 
tion and a great part of the ascending frontal convolution. 

The first includes those cases where no permanent hemi- 
plegia existed during life, and where autopsy discovered no 
consecutive degeneration. In all these cases the convolu- 
tions fed by the Sylvian artery, and especially the ascending 
frontal and parietal convolutions, had remained unharmed. 
The yellow patch occupied one of the following regions, 
namely, some part of the sphenoidal lobes, the quadrilateral 
lobule, the cuneus, one or both of the occipital lobes, and a 
region ranging over the anterior two-thirds of the frontal 
lobes. 



' The most of these observations are accompanied by designs made from nature ; 
it can be understood that the place and extent of the lesion are thus more exactly 
localeJ, and consequently the ordinary insufficiency of description is avoided. 



SECONDARY DEGENERATION. I 33 

In all cases of the second group, there had been, on the 
contrary, a permanent hemiplegia, and the consecutive sclero- 
sis was perfectly marked. The distinguishing feature of these 
cases was, that the lesion always involved more or less one or 
the other of the ascending frontal or parietal convolutions, 
chiefly in their superior half, and often both of the convolu- 
tions were at the same time affected ; besides, the regions 
nearest to the frontal and parietal convolutions generally 
participated. The design which I place before you is a very 
marked example (Fig. 45). 

From the preceding, as I before said, it would seem that 
secondary sclerosis, resulting from destructive lesions of the 
cerebral cortex, are subordinate to location. I will add, in 
conclusion, that those portions of the cortex a lesion of 
which determines secondary degenerations exclusively, cor- 
respond to those parts which experimentation with the mon- 
key has designated as the psycho-motor centres. They are 
the same also where the gray cortical substance contains the 
largest pyramidal cells, 

I have brought into relief an important fact, which should 
be utilized in the study of localization in the cerebral cortex ; 
a difficult study which we will attempt in our next lectures. 



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